From 5fb128539afcaf413856cc43bc92e90ef41d9a05 Mon Sep 17 00:00:00 2001
From: Craig Spence <craigspence0@gmail.com>
Date: Mon, 16 Sep 2024 17:56:10 +1200
Subject: [PATCH] =?UTF-8?q?fix(betterer=20=F0=9F=90=9B):=20improve=20docs,?=
 =?UTF-8?q?=20handle=20include=20and=20exclude,=20add=20tests,=20simplify?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .vscode/settings.json                         |   1 +
 packages/coverage/src/coverage-test.ts        |  11 +-
 packages/coverage/src/coverage.ts             |   4 +-
 packages/coverage/src/serialiser.ts           |   7 -
 packages/coverage/src/test.ts                 |  18 +-
 packages/coverage/src/types.ts                |  14 +-
 .../coverage-total-include.spec.ts.snap       | 132 +++++++++++++
 test/coverage-files-better.spec.ts            |  48 +++--
 test/coverage-files-exclude.spec.ts           |  44 +++--
 test/coverage-files-include.spec.ts           |  44 +++--
 test/coverage-files-same.spec.ts              | 102 +++++-----
 test/coverage-files-worse.spec.ts             | 182 +++++++++---------
 test/coverage-report-invalid.spec.ts          |  16 +-
 test/coverage-report-missing.spec.ts          |  12 +-
 test/coverage-total-include.spec.ts           | 144 ++++++++++++++
 test/coverage-total.spec.ts                   | 111 +++++++----
 website/docs/coverage-test.md                 |  11 +-
 17 files changed, 630 insertions(+), 271 deletions(-)
 delete mode 100644 packages/coverage/src/serialiser.ts
 create mode 100644 test/__snapshots__/coverage-total-include.spec.ts.snap
 create mode 100644 test/coverage-total-include.spec.ts

diff --git a/.vscode/settings.json b/.vscode/settings.json
index 9d752e831..ef5dc8dc6 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -17,6 +17,7 @@
     "docgen",
     "GOLDENS",
     "hasher",
+    "initialisation",
     "initialise",
     "initialised",
     "Initialising",
diff --git a/packages/coverage/src/coverage-test.ts b/packages/coverage/src/coverage-test.ts
index a3437f880..fd7b973d3 100644
--- a/packages/coverage/src/coverage-test.ts
+++ b/packages/coverage/src/coverage-test.ts
@@ -10,7 +10,6 @@ import { BettererResolverTest } from '@betterer/betterer';
 import { constraint } from './constraint.js';
 import { differ } from './differ.js';
 import { goal } from './goal.js';
-import { deserialise, serialise } from './serialiser.js';
 
 export class BettererCoverageTestΩ
   extends BettererResolverTest<BettererCoverageIssues, BettererCoverageIssues, BettererCoverageDiff>
@@ -18,16 +17,10 @@ export class BettererCoverageTestΩ
 {
   constructor(test: BettererCoverageTestFunction, coverageSummaryPath = './coverage/coverage-summary.json') {
     super({
-      test: async () => {
-        return await test(coverageSummaryPath, this.resolver);
-      },
+      test: async () => await test(coverageSummaryPath, this.resolver),
       constraint,
       differ,
-      goal,
-      serialiser: {
-        serialise,
-        deserialise
-      }
+      goal
     });
   }
 }
diff --git a/packages/coverage/src/coverage.ts b/packages/coverage/src/coverage.ts
index ed33d2477..c72c88d83 100644
--- a/packages/coverage/src/coverage.ts
+++ b/packages/coverage/src/coverage.ts
@@ -8,7 +8,7 @@ import { test, testTotal } from './test.js';
  * Use this test to track your per-file test coverage. Reads a {@link https://github.com/istanbuljs/istanbuljs/blob/master/packages/istanbul-reports/lib/json-summary/index.js | json-summary format}
  * coverage summary. Make sure to run your tests separately before running Betterer.
  *
- * @param coverageSummaryPath - relative path to the coverage summary. Defaults to './coverage/coverage-summary.json'.
+ * @param coverageSummaryPath - relative path to the coverage summary. Defaults to `'./coverage/coverage-summary.json'`.
  */
 export function coverage(coverageSummaryPath?: string): BettererCoverageTest {
   return new BettererCoverageTestΩ(test, coverageSummaryPath);
@@ -19,7 +19,7 @@ export function coverage(coverageSummaryPath?: string): BettererCoverageTest {
  * Use this test to track your total test coverage. Reads a {@link https://github.com/istanbuljs/istanbuljs/blob/master/packages/istanbul-reports/lib/json-summary/index.js | json-summary format}
  * coverage summary. Make sure to run your tests separately before running Betterer.
  *
- * @param coverageSummaryPath - relative path to the coverage summary. Defaults to './coverage/coverage-summary.json'.
+ * @param coverageSummaryPath - relative path to the coverage summary. Defaults to `'./coverage/coverage-summary.json'`.
  */
 export function coverageTotal(coverageSummaryPath?: string): BettererCoverageTest {
   return new BettererCoverageTestΩ(testTotal, coverageSummaryPath);
diff --git a/packages/coverage/src/serialiser.ts b/packages/coverage/src/serialiser.ts
deleted file mode 100644
index f95366e1e..000000000
--- a/packages/coverage/src/serialiser.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-export function deserialise<T>(serialised: T): T {
-  return serialised;
-}
-
-export function serialise<T>(input: T): T {
-  return input;
-}
diff --git a/packages/coverage/src/test.ts b/packages/coverage/src/test.ts
index d0d8c71c0..5b090fd25 100644
--- a/packages/coverage/src/test.ts
+++ b/packages/coverage/src/test.ts
@@ -40,11 +40,21 @@ export async function testTotal(
   relativeCoverageSummaryPath: string,
   resolver: BettererFileResolver
 ): Promise<BettererCoverageIssues> {
-  const absoluteCoverageSummaryPath = resolver.resolve(relativeCoverageSummaryPath);
-  const { total } = await readCoverageSummary(absoluteCoverageSummaryPath);
-  return {
-    total: getUncoveredIssues(total)
+  const uncovered = await test(relativeCoverageSummaryPath, resolver);
+
+  const total: BettererCoverageIssue = {
+    lines: 0,
+    statements: 0,
+    functions: 0,
+    branches: 0
   };
+  Object.values(uncovered).forEach((fileCoverage) => {
+    total.branches += fileCoverage.branches;
+    total.functions += fileCoverage.functions;
+    total.lines += fileCoverage.lines;
+    total.statements += fileCoverage.statements;
+  });
+  return { total };
 }
 
 async function readCoverageSummary(coverageSummaryPath: string): Promise<IstanbulCoverageSummary> {
diff --git a/packages/coverage/src/types.ts b/packages/coverage/src/types.ts
index 29a0c8f94..f8ca576d7 100644
--- a/packages/coverage/src/types.ts
+++ b/packages/coverage/src/types.ts
@@ -3,9 +3,7 @@ import type { CoverageSummaryData, Totals } from 'istanbul-lib-coverage';
 
 export type IstanbulCoverage = Totals;
 export type IstanbulFileCoverage = CoverageSummaryData;
-export type IstanbulCoverageSummary = Record<string, IstanbulFileCoverage> & {
-  total: IstanbulFileCoverage;
-};
+export type IstanbulCoverageSummary = Record<string, IstanbulFileCoverage>;
 
 /**
  * @public A {@link @betterer/betterer#BettererTest | `BettererTest`} to incrementally improve test coverage.
@@ -22,21 +20,23 @@ export type BettererCoverageTestFunction = (
 ) => Promise<BettererCoverageIssues>;
 
 /**
- * @public The different types of coverage which are checked
+ * @public The different types of coverage which are checked.
  */
 export type BettererCoverageTypes = 'lines' | 'statements' | 'functions' | 'branches';
 
 /**
- * @public The lines, statements, functions and branches coverage for a file (or the total project)
+ * @public The lines, statements, functions and branches coverage for a file (or the total project).
+ *
+ * @remarks Each value indicates how many of each type remain uncovered in the file.
  */
 export type BettererCoverageIssue = Record<BettererCoverageTypes, number>;
 
 /**
- * @public The coverage for all the files in a project
+ * @public The coverage for all the files in a project.
  */
 export type BettererCoverageIssues = Record<string, BettererCoverageIssue>;
 
 /**
- * @public The difference in coverage for a project between two test runs
+ * @public The difference in coverage for a project between two test runs.
  */
 export type BettererCoverageDiff = BettererCoverageIssues;
diff --git a/test/__snapshots__/coverage-total-include.spec.ts.snap b/test/__snapshots__/coverage-total-include.spec.ts.snap
new file mode 100644
index 000000000..eb1a05b60
--- /dev/null
+++ b/test/__snapshots__/coverage-total-include.spec.ts.snap
@@ -0,0 +1,132 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`betterer > should report the total coverage for included files 1`] = `
+"// BETTERER RESULTS V2.
+//
+// If this file contains merge conflicts, use \`betterer merge\` to automatically resolve them:
+// https://phenomnomnominal.github.io/betterer/docs/results-file/#merge
+//
+exports[\`test\`] = {
+  value: \`{
+  "total": { "lines": 50, "statements": 130, "functions": 15, "branches": 100 }
+}
+\`
+};
+"
+`;
+
+exports[`betterer > should report the total coverage for included files 2`] = `
+"// BETTERER RESULTS V2.
+//
+// If this file contains merge conflicts, use \`betterer merge\` to automatically resolve them:
+// https://phenomnomnominal.github.io/betterer/docs/results-file/#merge
+//
+exports[\`test\`] = {
+  value: \`{
+  "total": { "lines": 30, "statements": 130, "functions": 15, "branches": 100 }
+}
+\`
+};
+"
+`;
+
+exports[`betterer > should report the total coverage for included files 3`] = `
+"// BETTERER RESULTS V2.
+//
+// If this file contains merge conflicts, use \`betterer merge\` to automatically resolve them:
+// https://phenomnomnominal.github.io/betterer/docs/results-file/#merge
+//
+exports[\`test\`] = {
+  value: \`{
+  "total": { "lines": 30, "statements": 130, "functions": 15, "branches": 100 }
+}
+\`
+};
+"
+`;
+
+exports[`betterer > should report the total coverage for included files 4`] = `
+[
+  "🌟 Betterer (0ms):
+",
+  "🌟 Betterer (0ms): 1 test running...
+🤔 test: running "test"!
+",
+  "🌟 Betterer (0ms): 1 test running...
+✅ test: "test" got checked for the first time! 🎉
+",
+  "🎉 Betterer (0ms): 1 test done!
+✅ test: "test" got checked for the first time! 🎉
+",
+  "🎉 Betterer (0ms): 1 test done!
+✅ test: "test" got checked for the first time! 🎉
+
+1 test got checked. 🤔
+1 test got checked for the first time! 🎉
+",
+  "🌟 Betterer (0ms):
+",
+  "🌟 Betterer (0ms): 1 test running...
+🤔 test: running "test"!
+",
+  "🌟 Betterer (0ms): 1 test running...
+✅ test: "test" stayed the same. 😐
+",
+  "🎉 Betterer (0ms): 1 test done!
+✅ test: "test" stayed the same. 😐
+",
+  "🎉 Betterer (0ms): 1 test done!
+✅ test: "test" stayed the same. 😐
+
+1 test got checked. 🤔
+1 test stayed the same. 😐
+",
+  "🌟 Betterer (0ms):
+",
+  "🌟 Betterer (0ms): 1 test running...
+🤔 test: running "test"!
+",
+  "🌟 Betterer (0ms): 1 test running...
+✅ test: "test" got better! 😍
+",
+  "🎉 Betterer (0ms): 1 test done!
+✅ test: "test" got better! 😍
+",
+  "🎉 Betterer (0ms): 1 test done!
+✅ test: "test" got better! 😍
+
+1 test got checked. 🤔
+1 test got better! 😍
+",
+  "🌟 Betterer (0ms):
+",
+  "🌟 Betterer (0ms): 1 test running...
+🤔 test: running "test"!
+",
+  "🌟 Betterer (0ms): 1 test running...
+🔥 test: "test" got worse. 😔
+",
+  "🌟 Betterer (0ms): 1 test running...
+🔥 test: "test" got worse. 😔
+
+Error: "test" got worse. 😔
+",
+  "💥 Betterer (0ms): 1 test done! 1 test errored!
+🔥 test: "test" got worse. 😔
+・ "lines" coverage is worse in "total": 60 > 30
+
+Error: "test" got worse. 😔
+",
+  "💥 Betterer (0ms): 1 test done! 1 test errored!
+🔥 test: "test" got worse. 😔
+・ "lines" coverage is worse in "total": 60 > 30
+
+Error: "test" got worse. 😔
+
+1 test got checked. 🤔
+1 test got worse. 😔
+
+You should try to fix the new issues! As a last resort, you can run \`betterer --update\` to force an update of the results file. 🆙
+",
+]
+`;
diff --git a/test/coverage-files-better.spec.ts b/test/coverage-files-better.spec.ts
index c7c8ccdc1..4bb7224bb 100644
--- a/test/coverage-files-better.spec.ts
+++ b/test/coverage-files-better.spec.ts
@@ -6,7 +6,7 @@ describe('betterer', () => {
   it('should report an improved file coverage result', async () => {
     const { betterer } = await import('@betterer/betterer');
 
-    const fixture = await createFixture('coverage-files-better', {
+    const { paths, logs, cleanup, resolve, testNames, writeFile } = await createFixture('coverage-files-better', {
       '.betterer.js': `
 import { coverage } from '@betterer/coverage';
 
@@ -22,10 +22,11 @@ export default {
       `
     });
 
-    const file1Path = fixture.resolve('./src/file-1.ts');
-    const file2Path = fixture.resolve('./src/file-2.ts');
+    const file1Path = resolve('./src/file-1.ts');
+    const file2Path = resolve('./src/file-2.ts');
 
-    const coverage = `{  
+    const coverage = `
+{
   "total": {
     "lines": { "total": 220, "covered": 110, "skipped": 0, "pct": 50 },
     "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
@@ -44,18 +45,20 @@ export default {
     "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
     "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
   }
-}`;
+}
+    `;
 
-    const configPaths = [fixture.paths.config];
-    const resultsPath = fixture.paths.results;
-    const coveragePath = fixture.resolve('./coverage/coverage-summary.json');
+    const configPaths = [paths.config];
+    const resultsPath = paths.results;
+    const coveragePath = resolve('./coverage/coverage-summary.json');
 
-    await fixture.writeFile(coveragePath, coverage);
+    await writeFile(coveragePath, coverage);
 
     await betterer({ configPaths, resultsPath, workers: false });
 
     // file-1 is better
-    const betterCoverage = `{
+    const betterCoverage = `
+{
   "total": {
     "lines": { "total": 220, "covered": 120, "skipped": 0, "pct": 54.54 },
     "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
@@ -74,16 +77,18 @@ export default {
     "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
     "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
   }
-}`;
+}
+    `;
 
-    await fixture.writeFile(coveragePath, betterCoverage);
+    await writeFile(coveragePath, betterCoverage);
 
     const betterTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(betterTestRun.better)).toEqual(['test']);
+    expect(testNames(betterTestRun.better)).toEqual(['test']);
 
     // file-1 is gone
-    const evenBetterCoverage = `{
+    const evenBetterCoverage = `
+{
   "total": {
     "lines": { "total": 120, "covered": 60, "skipped": 0, "pct": 50 },
     "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
@@ -96,13 +101,14 @@ export default {
     "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
     "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
   }
-}`;
+}
+    `;
 
-    await fixture.writeFile(coveragePath, evenBetterCoverage);
+    await writeFile(coveragePath, evenBetterCoverage);
 
     const evenBetterTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(evenBetterTestRun.better)).toEqual(['test']);
+    expect(testNames(evenBetterTestRun.better)).toEqual(['test']);
 
     // file-2 is fully covered
     const completedCoverage = `{
@@ -120,14 +126,14 @@ export default {
   }
 }`;
 
-    await fixture.writeFile(coveragePath, completedCoverage);
+    await writeFile(coveragePath, completedCoverage);
 
     const completedTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(completedTestRun.completed)).toEqual(['test']);
+    expect(testNames(completedTestRun.completed)).toEqual(['test']);
 
-    expect(fixture.logs).toMatchSnapshot();
+    expect(logs).toMatchSnapshot();
 
-    await fixture.cleanup();
+    await cleanup();
   });
 });
diff --git a/test/coverage-files-exclude.spec.ts b/test/coverage-files-exclude.spec.ts
index a35ba1dfe..0350800f6 100644
--- a/test/coverage-files-exclude.spec.ts
+++ b/test/coverage-files-exclude.spec.ts
@@ -6,7 +6,7 @@ describe('betterer', () => {
   it('should work when excluding specific files', async () => {
     const { betterer } = await import('@betterer/betterer');
 
-    const fixture = await createFixture('coverage-files-exclude', {
+    const { paths, logs, cleanup, resolve, testNames, writeFile } = await createFixture('coverage-files-exclude', {
       '.betterer.js': `
 import { coverage } from '@betterer/coverage';
 
@@ -22,10 +22,11 @@ export default {
       `
     });
 
-    const file1Path = fixture.resolve('./src/file-1.ts');
-    const file2Path = fixture.resolve('./src/file-2.ts');
+    const file1Path = resolve('./src/file-1.ts');
+    const file2Path = resolve('./src/file-2.ts');
 
-    const coverage = `{  
+    const coverage = `
+{
   "total": {
     "lines": { "total": 220, "covered": 110, "skipped": 0, "pct": 50 },
     "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
@@ -44,18 +45,20 @@ export default {
     "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
     "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
   }
-}`;
+}
+    `;
 
-    const configPaths = [fixture.paths.config];
-    const resultsPath = fixture.paths.results;
-    const coveragePath = fixture.resolve('./coverage/coverage-summary.json');
+    const configPaths = [paths.config];
+    const resultsPath = paths.results;
+    const coveragePath = resolve('./coverage/coverage-summary.json');
 
-    await fixture.writeFile(coveragePath, coverage);
+    await writeFile(coveragePath, coverage);
 
     await betterer({ configPaths, resultsPath, workers: false });
 
     // file-1 is better
-    const betterCoverage = `{
+    const betterCoverage = `
+{
   "total": {
     "lines": { "total": 220, "covered": 120, "skipped": 0, "pct": 54.54 },
     "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
@@ -74,16 +77,18 @@ export default {
     "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
     "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
   }
-}`;
+}
+    `;
 
-    await fixture.writeFile(coveragePath, betterCoverage);
+    await writeFile(coveragePath, betterCoverage);
 
     const betterTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(betterTestRun.better)).toEqual(['test']);
+    expect(testNames(betterTestRun.better)).toEqual(['test']);
 
     // file-2 is worse (but result is the same because it's excluded)
-    const sameCoverage = `{
+    const sameCoverage = `
+{
   "total": {
     "lines": { "total": 220, "covered": 100, "skipped": 0, "pct": 45.4 },
     "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
@@ -102,16 +107,17 @@ export default {
     "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
     "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
   }
-}`;
+}
+    `;
 
-    await fixture.writeFile(coveragePath, sameCoverage);
+    await writeFile(coveragePath, sameCoverage);
 
     const sameTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(sameTestRun.same)).toEqual(['test']);
+    expect(testNames(sameTestRun.same)).toEqual(['test']);
 
-    expect(fixture.logs).toMatchSnapshot();
+    expect(logs).toMatchSnapshot();
 
-    await fixture.cleanup();
+    await cleanup();
   });
 });
diff --git a/test/coverage-files-include.spec.ts b/test/coverage-files-include.spec.ts
index 52312eda3..18246d243 100644
--- a/test/coverage-files-include.spec.ts
+++ b/test/coverage-files-include.spec.ts
@@ -6,7 +6,7 @@ describe('betterer', () => {
   it('should work when including specific files', async () => {
     const { betterer } = await import('@betterer/betterer');
 
-    const fixture = await createFixture('coverage-files-include', {
+    const { paths, logs, cleanup, resolve, testNames, writeFile } = await createFixture('coverage-files-include', {
       '.betterer.ts': `
 import { coverage } from '@betterer/coverage';
 
@@ -22,10 +22,11 @@ export default {
       `
     });
 
-    const file1Path = fixture.resolve('./src/file-1.ts');
-    const file2Path = fixture.resolve('./src/file-2.ts');
+    const file1Path = resolve('./src/file-1.ts');
+    const file2Path = resolve('./src/file-2.ts');
 
-    const coverage = `{  
+    const coverage = `
+{  
   "total": {
     "lines": { "total": 220, "covered": 110, "skipped": 0, "pct": 50 },
     "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
@@ -44,18 +45,20 @@ export default {
     "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
     "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
   }
-}`;
+}
+    `;
 
-    const configPaths = [fixture.paths.config];
-    const resultsPath = fixture.paths.results;
-    const coveragePath = fixture.resolve('./coverage/coverage-summary.json');
+    const configPaths = [paths.config];
+    const resultsPath = paths.results;
+    const coveragePath = resolve('./coverage/coverage-summary.json');
 
-    await fixture.writeFile(coveragePath, coverage);
+    await writeFile(coveragePath, coverage);
 
     await betterer({ configPaths, resultsPath, workers: false });
 
     // file-1 is better
-    const betterCoverage = `{
+    const betterCoverage = `
+{
   "total": {
     "lines": { "total": 220, "covered": 120, "skipped": 0, "pct": 54.54 },
     "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
@@ -74,16 +77,18 @@ export default {
     "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
     "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
   }
-}`;
+}
+    `;
 
-    await fixture.writeFile(coveragePath, betterCoverage);
+    await writeFile(coveragePath, betterCoverage);
 
     const betterTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(betterTestRun.better)).toEqual(['test']);
+    expect(testNames(betterTestRun.better)).toEqual(['test']);
 
     // file-2 is worse (but result is the same because it's ignored)
-    const sameCoverage = `{
+    const sameCoverage = `
+{
   "total": {
     "lines": { "total": 220, "covered": 100, "skipped": 0, "pct": 45.4 },
     "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
@@ -102,16 +107,17 @@ export default {
     "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
     "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
   }
-}`;
+}
+    `;
 
-    await fixture.writeFile(coveragePath, sameCoverage);
+    await writeFile(coveragePath, sameCoverage);
 
     const sameTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(sameTestRun.same)).toEqual(['test']);
+    expect(testNames(sameTestRun.same)).toEqual(['test']);
 
-    expect(fixture.logs).toMatchSnapshot();
+    expect(logs).toMatchSnapshot();
 
-    await fixture.cleanup();
+    await cleanup();
   });
 });
diff --git a/test/coverage-files-same.spec.ts b/test/coverage-files-same.spec.ts
index 0e053470a..850c84139 100644
--- a/test/coverage-files-same.spec.ts
+++ b/test/coverage-files-same.spec.ts
@@ -6,27 +6,31 @@ describe('betterer', () => {
   it('should report a stable per-file coverage result', async () => {
     const { betterer } = await import('@betterer/betterer');
 
-    const fixture = await createFixture('coverage-files-same', {
-      '.betterer.js': `
+    const { paths, logs, cleanup, resolve, testNames, readFile, writeFile } = await createFixture(
+      'coverage-files-same',
+      {
+        '.betterer.js': `
 import { coverage } from '@betterer/coverage';
 
 export default {
   test: () => coverage()
 };    
         `,
-      'tsconfig.json': `
+        'tsconfig.json': `
 {
   "extends": "../../tsconfig.json",
   "include": ["./src/**/*", "./.betterer.js"]
 }
-      `
-    });
+        `
+      }
+    );
 
-    const file1Path = fixture.resolve('./src/file-1.ts');
-    const file2Path = fixture.resolve('./src/file-2.ts');
-    const file3Path = fixture.resolve('./src/file-3.ts');
+    const file1Path = resolve('./src/file-1.ts');
+    const file2Path = resolve('./src/file-2.ts');
+    const file3Path = resolve('./src/file-3.ts');
 
-    const coverage = `{  
+    const coverage = `
+{  
   "total": {
     "lines": { "total": 220, "covered": 110, "skipped": 0, "pct": 50 },
     "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
@@ -45,62 +49,66 @@ export default {
     "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
     "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
   }
-}`;
+}
+    `;
 
-    const configPaths = [fixture.paths.config];
-    const resultsPath = fixture.paths.results;
-    const coveragePath = fixture.resolve('./coverage/coverage-summary.json');
+    const configPaths = [paths.config];
+    const resultsPath = paths.results;
+    const coveragePath = resolve('./coverage/coverage-summary.json');
 
-    await fixture.writeFile(coveragePath, coverage);
+    await writeFile(coveragePath, coverage);
 
     const newTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(newTestRun.new)).toEqual(['test']);
+    expect(testNames(newTestRun.new)).toEqual(['test']);
 
     await betterer({ configPaths, resultsPath, workers: false });
     const sameTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(sameTestRun.same)).toEqual(['test']);
+    expect(testNames(sameTestRun.same)).toEqual(['test']);
+
+    const result = await readFile(resultsPath);
 
-    const result = await fixture.readFile(resultsPath);
     expect(result).toMatchSnapshot();
 
     // file-3 is added but it is 100% covered
-    const stillSameCoverage = `{  
-      "total": {
-        "lines": { "total": 220, "covered": 110, "skipped": 0, "pct": 50 },
-        "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
-        "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
-        "branches": { "total": 300, "covered": 100, "skipped": 0, "pct": 33.3 }
-      },
-      "${file1Path}": {
-        "lines": { "total": 100, "covered": 50, "skipped": 0, "pct": 50 },
-        "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
-        "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
-        "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
-      },
-      "${file2Path}": {
-        "lines": { "total": 120, "covered": 60, "skipped": 0, "pct": 50 },
-        "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
-        "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
-        "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
-      },
-      "${file3Path}": {
-        "lines": { "total": 120, "covered": 120, "skipped": 0, "pct": 100 },
-        "statements": { "total": 210, "covered": 210, "skipped": 0, "pct": 100 },
-        "functions": { "total": 10, "covered": 10, "skipped": 0, "pct": 100 },
-        "branches": { "total": 150, "covered": 150, "skipped": 0, "pct": 100 }
-      }
-    }`;
+    const stillSameCoverage = `
+{  
+  "total": {
+    "lines": { "total": 220, "covered": 110, "skipped": 0, "pct": 50 },
+    "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
+    "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
+    "branches": { "total": 300, "covered": 100, "skipped": 0, "pct": 33.3 }
+  },
+  "${file1Path}": {
+    "lines": { "total": 100, "covered": 50, "skipped": 0, "pct": 50 },
+    "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
+    "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  },
+  "${file2Path}": {
+    "lines": { "total": 120, "covered": 60, "skipped": 0, "pct": 50 },
+    "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
+    "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  },
+  "${file3Path}": {
+    "lines": { "total": 120, "covered": 120, "skipped": 0, "pct": 100 },
+    "statements": { "total": 210, "covered": 210, "skipped": 0, "pct": 100 },
+    "functions": { "total": 10, "covered": 10, "skipped": 0, "pct": 100 },
+    "branches": { "total": 150, "covered": 150, "skipped": 0, "pct": 100 }
+  }
+}
+    `;
 
-    await fixture.writeFile(coveragePath, stillSameCoverage);
+    await writeFile(coveragePath, stillSameCoverage);
 
     const stillSameTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(stillSameTestRun.same)).toEqual(['test']);
+    expect(testNames(stillSameTestRun.same)).toEqual(['test']);
 
-    expect(fixture.logs).toMatchSnapshot();
+    expect(logs).toMatchSnapshot();
 
-    await fixture.cleanup();
+    await cleanup();
   });
 });
diff --git a/test/coverage-files-worse.spec.ts b/test/coverage-files-worse.spec.ts
index b12964a4d..234a1b012 100644
--- a/test/coverage-files-worse.spec.ts
+++ b/test/coverage-files-worse.spec.ts
@@ -6,7 +6,7 @@ describe('betterer', () => {
   it('should report a worse file coverage result', async () => {
     const { betterer } = await import('@betterer/betterer');
 
-    const fixture = await createFixture('coverage-files-worse', {
+    const { paths, logs, cleanup, resolve, testNames, writeFile } = await createFixture('coverage-files-worse', {
       '.betterer.js': `
 import { coverage } from '@betterer/coverage';
 
@@ -22,11 +22,12 @@ export default {
       `
     });
 
-    const file1Path = fixture.resolve('./src/file-1.ts');
-    const file2Path = fixture.resolve('./src/file-2.ts');
-    const file3Path = fixture.resolve('./src/file-3.ts');
+    const file1Path = resolve('./src/file-1.ts');
+    const file2Path = resolve('./src/file-2.ts');
+    const file3Path = resolve('./src/file-3.ts');
 
-    const coverage = `{  
+    const coverage = `
+{  
   "total": {
     "lines": { "total": 220, "covered": 110, "skipped": 0, "pct": 50 },
     "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
@@ -45,108 +46,115 @@ export default {
     "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
     "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
   }
-}`;
+}
+    `;
 
-    const configPaths = [fixture.paths.config];
-    const resultsPath = fixture.paths.results;
-    const coveragePath = fixture.resolve('./coverage/coverage-summary.json');
+    const configPaths = [paths.config];
+    const resultsPath = paths.results;
+    const coveragePath = resolve('./coverage/coverage-summary.json');
 
-    await fixture.writeFile(coveragePath, coverage);
+    await writeFile(coveragePath, coverage);
 
     await betterer({ configPaths, resultsPath, workers: false });
 
     // file-1 is worse
-    const worseCoverage = `{  
-      "total": {
-        "lines": { "total": 220, "covered": 100, "skipped": 0, "pct": 45.4 },
-        "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
-        "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
-        "branches": { "total": 300, "covered": 100, "skipped": 0, "pct": 33.3 }
-      },
-      "${file1Path}": {
-        "lines": { "total": 100, "covered": 40, "skipped": 0, "pct": 40 },
-        "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
-        "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
-        "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
-      },
-      "${file2Path}": {
-        "lines": { "total": 120, "covered": 60, "skipped": 0, "pct": 50 },
-        "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
-        "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
-        "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
-      }
-    }`;
-
-    await fixture.writeFile(coveragePath, worseCoverage);
+    const worseCoverage = `
+{  
+  "total": {
+    "lines": { "total": 220, "covered": 100, "skipped": 0, "pct": 45.4 },
+    "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
+    "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
+    "branches": { "total": 300, "covered": 100, "skipped": 0, "pct": 33.3 }
+  },
+  "${file1Path}": {
+    "lines": { "total": 100, "covered": 40, "skipped": 0, "pct": 40 },
+    "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
+    "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  },
+  "${file2Path}": {
+    "lines": { "total": 120, "covered": 60, "skipped": 0, "pct": 50 },
+    "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
+    "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  }
+}
+    `;
+
+    await writeFile(coveragePath, worseCoverage);
 
     const worseTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(worseTestRun.worse)).toEqual(['test']);
+    expect(testNames(worseTestRun.worse)).toEqual(['test']);
 
     // file-1 is better, but file-2 is worse
-    const stillWorseCoverage = `{
-      "total": {
-        "lines": { "total": 220, "covered": 90, "skipped": 0, "pct": 40.9 },
-        "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
-        "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
-        "branches": { "total": 300, "covered": 100, "skipped": 0, "pct": 33.3 }
-      },
-      "${file1Path}": {
-        "lines": { "total": 100, "covered": 60, "skipped": 0, "pct": 60 },
-        "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
-        "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
-        "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
-      },
-      "${file2Path}": {
-        "lines": { "total": 120, "covered": 30, "skipped": 0, "pct": 25 },
-        "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
-        "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
-        "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
-      }
-    }`;
-
-    await fixture.writeFile(coveragePath, stillWorseCoverage);
+    const stillWorseCoverage = `
+{
+  "total": {
+    "lines": { "total": 220, "covered": 90, "skipped": 0, "pct": 40.9 },
+    "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
+    "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
+    "branches": { "total": 300, "covered": 100, "skipped": 0, "pct": 33.3 }
+  },
+  "${file1Path}": {
+    "lines": { "total": 100, "covered": 60, "skipped": 0, "pct": 60 },
+    "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
+    "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  },
+  "${file2Path}": {
+    "lines": { "total": 120, "covered": 30, "skipped": 0, "pct": 25 },
+    "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
+    "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  }
+}
+    `;
+
+    await writeFile(coveragePath, stillWorseCoverage);
 
     const stillWorseTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(stillWorseTestRun.worse)).toEqual(['test']);
+    expect(testNames(stillWorseTestRun.worse)).toEqual(['test']);
 
     // file-3 is added but it is not 100% covered
-    const evenWorseCoverage = `{  
-      "total": {
-        "lines": { "total": 320, "covered": 150, "skipped": 0, "pct": 46.8 },
-        "statements": { "total": 610, "covered": 210, "skipped": 0, "pct": 34.4 },
-        "functions": { "total": 50, "covered": 16, "skipped": 0, "pct": 32 },
-        "branches": { "total": 450, "covered": 150, "skipped": 0, "pct": 33.3 }
-      },
-      "${file1Path}": {
-        "lines": { "total": 100, "covered": 60, "skipped": 0, "pct": 60 },
-        "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
-        "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
-        "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
-      },
-      "${file2Path}": {
-        "lines": { "total": 120, "covered": 30, "skipped": 0, "pct": 25 },
-        "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
-        "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
-        "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
-      },
-      "${file3Path}": {
-        "lines": { "total": 100, "covered": 60, "skipped": 0, "pct": 60 },
-        "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
-        "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
-        "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
-      }
-    }`;
-
-    await fixture.writeFile(coveragePath, evenWorseCoverage);
+    const evenWorseCoverage = `
+{  
+  "total": {
+    "lines": { "total": 320, "covered": 150, "skipped": 0, "pct": 46.8 },
+    "statements": { "total": 610, "covered": 210, "skipped": 0, "pct": 34.4 },
+    "functions": { "total": 50, "covered": 16, "skipped": 0, "pct": 32 },
+    "branches": { "total": 450, "covered": 150, "skipped": 0, "pct": 33.3 }
+  },
+  "${file1Path}": {
+    "lines": { "total": 100, "covered": 60, "skipped": 0, "pct": 60 },
+    "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
+    "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  },
+  "${file2Path}": {
+    "lines": { "total": 120, "covered": 30, "skipped": 0, "pct": 25 },
+    "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
+    "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  },
+  "${file3Path}": {
+    "lines": { "total": 100, "covered": 60, "skipped": 0, "pct": 60 },
+    "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
+    "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  }
+}
+    `;
+
+    await writeFile(coveragePath, evenWorseCoverage);
 
     const evenWorseTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(evenWorseTestRun.worse)).toEqual(['test']);
+    expect(testNames(evenWorseTestRun.worse)).toEqual(['test']);
 
-    expect(fixture.logs).toMatchSnapshot();
+    expect(logs).toMatchSnapshot();
 
-    await fixture.cleanup();
+    await cleanup();
   });
 });
diff --git a/test/coverage-report-invalid.spec.ts b/test/coverage-report-invalid.spec.ts
index 1422b7516..92559e3d6 100644
--- a/test/coverage-report-invalid.spec.ts
+++ b/test/coverage-report-invalid.spec.ts
@@ -6,7 +6,7 @@ describe('betterer', () => {
   it('should fail when the coverage report is invalid', async () => {
     const { betterer } = await import('@betterer/betterer');
 
-    const fixture = await createFixture('coverage-report-invalid', {
+    const { paths, logs, cleanup, resolve, testNames, writeFile } = await createFixture('coverage-report-invalid', {
       '.betterer.js': `
 import { coverageTotal } from '@betterer/coverage';
 
@@ -30,18 +30,18 @@ export default {
   }
 }`;
 
-    const configPaths = [fixture.paths.config];
-    const resultsPath = fixture.paths.results;
-    const coveragePath = fixture.resolve('./coverage/coverage-summary.json');
+    const configPaths = [paths.config];
+    const resultsPath = paths.results;
+    const coveragePath = resolve('./coverage/coverage-summary.json');
 
-    await fixture.writeFile(coveragePath, coverage);
+    await writeFile(coveragePath, coverage);
 
     const newTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(newTestRun.failed)).toEqual(['test']);
+    expect(testNames(newTestRun.failed)).toEqual(['test']);
 
-    expect(fixture.logs).toMatchSnapshot();
+    expect(logs).toMatchSnapshot();
 
-    await fixture.cleanup();
+    await cleanup();
   });
 });
diff --git a/test/coverage-report-missing.spec.ts b/test/coverage-report-missing.spec.ts
index b98a73332..837ad6f22 100644
--- a/test/coverage-report-missing.spec.ts
+++ b/test/coverage-report-missing.spec.ts
@@ -6,7 +6,7 @@ describe('betterer', () => {
   it('should fail when the coverage report is missing', async () => {
     const { betterer } = await import('@betterer/betterer');
 
-    const fixture = await createFixture('coverage-report-missing', {
+    const { paths, logs, cleanup, testNames } = await createFixture('coverage-report-missing', {
       '.betterer.js': `
 import { coverageTotal } from '@betterer/coverage';
 
@@ -22,15 +22,15 @@ export default {
       `
     });
 
-    const configPaths = [fixture.paths.config];
-    const resultsPath = fixture.paths.results;
+    const configPaths = [paths.config];
+    const resultsPath = paths.results;
 
     const newTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(newTestRun.failed)).toEqual(['test']);
+    expect(testNames(newTestRun.failed)).toEqual(['test']);
 
-    expect(fixture.logs).toMatchSnapshot();
+    expect(logs).toMatchSnapshot();
 
-    await fixture.cleanup();
+    await cleanup();
   });
 });
diff --git a/test/coverage-total-include.spec.ts b/test/coverage-total-include.spec.ts
new file mode 100644
index 000000000..4b4dccdcd
--- /dev/null
+++ b/test/coverage-total-include.spec.ts
@@ -0,0 +1,144 @@
+import { describe, expect, it } from 'vitest';
+
+import { createFixture } from './fixture.js';
+
+describe('betterer', () => {
+  it('should report the total coverage for included files', async () => {
+    const { betterer } = await import('@betterer/betterer');
+
+    const { paths, logs, cleanup, resolve, readFile, testNames, writeFile } = await createFixture(
+      'coverage-total-include',
+      {
+        '.betterer.js': `
+import { coverageTotal } from '@betterer/coverage';
+
+export default {
+  test: () => coverageTotal('./my-report/coverage.json').include('**/file-1.ts')
+};    
+        `,
+        'tsconfig.json': `
+{
+  "extends": "../../tsconfig.json",
+  "include": ["./src/**/*", "./.betterer.js"]
+}
+      `
+      }
+    );
+
+    const file1Path = resolve('./src/file-1.ts');
+    const file2Path = resolve('./src/file-2.ts');
+
+    const coverage = `
+{
+  "total": {
+    "lines": { "total": 220, "covered": 110, "skipped": 0, "pct": 50 },
+    "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
+    "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
+    "branches": { "total": 300, "covered": 100, "skipped": 0, "pct": 33.3 }
+  },
+  "${file1Path}": {
+    "lines": { "total": 100, "covered": 50, "skipped": 0, "pct": 50 },
+    "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
+    "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  },
+  "${file2Path}": {
+    "lines": { "total": 120, "covered": 60, "skipped": 0, "pct": 50 },
+    "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
+    "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  }
+}
+    `;
+
+    const configPaths = [paths.config];
+    const resultsPath = paths.results;
+    const coveragePath = resolve('./my-report/coverage.json');
+
+    await writeFile(coveragePath, coverage);
+
+    const newTestRun = await betterer({ configPaths, resultsPath, workers: false });
+
+    expect(testNames(newTestRun.new)).toEqual(['test']);
+
+    const newResult = await readFile(resultsPath);
+
+    expect(newResult).toMatchSnapshot();
+
+    const sameTestRun = await betterer({ configPaths, resultsPath, workers: false });
+
+    expect(testNames(sameTestRun.same)).toEqual(['test']);
+
+    // Included file gets better, ignored file gets worse:
+    const betterCoverage = `
+{
+  "total": {
+    "lines": { "total": 220, "covered": 110, "skipped": 0, "pct": 61.9 },
+    "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
+    "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
+    "branches": { "total": 300, "covered": 100, "skipped": 0, "pct": 33.3 }
+  },
+  "${file1Path}": {
+    "lines": { "total": 100, "covered": 70, "skipped": 0, "pct": 50 },
+    "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
+    "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  },
+  "${file2Path}": {
+    "lines": { "total": 120, "covered": 40, "skipped": 0, "pct": 33.3 },
+    "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
+    "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  }
+}
+    `;
+
+    await writeFile(coveragePath, betterCoverage);
+
+    const betterTestRun = await betterer({ configPaths, resultsPath, workers: false });
+
+    expect(testNames(betterTestRun.better)).toEqual(['test']);
+
+    const betterResult = await readFile(resultsPath);
+
+    expect(betterResult).toMatchSnapshot();
+
+    // Included file gets worse, included file gets better:
+    const worseCoverage = `
+{
+  "total": {
+    "lines": { "total": 220, "covered": 110, "skipped": 0, "pct": 61.9 },
+    "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
+    "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
+    "branches": { "total": 300, "covered": 100, "skipped": 0, "pct": 33.3 }
+  },
+  "${file1Path}": {
+    "lines": { "total": 100, "covered": 40, "skipped": 0, "pct": 40 },
+    "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
+    "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  },
+  "${file2Path}": {
+    "lines": { "total": 120, "covered": 80, "skipped": 0, "pct": 66.6 },
+    "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
+    "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  }
+}
+    `;
+
+    await writeFile(coveragePath, worseCoverage);
+
+    const worseTestRun = await betterer({ configPaths, resultsPath, workers: false });
+
+    expect(testNames(worseTestRun.worse)).toEqual(['test']);
+
+    const worseResult = await readFile(resultsPath);
+
+    expect(worseResult).toMatchSnapshot();
+
+    expect(logs).toMatchSnapshot();
+
+    await cleanup();
+  });
+});
diff --git a/test/coverage-total.spec.ts b/test/coverage-total.spec.ts
index a681a586a..fc942a973 100644
--- a/test/coverage-total.spec.ts
+++ b/test/coverage-total.spec.ts
@@ -6,12 +6,12 @@ describe('betterer', () => {
   it('should report the total coverage', async () => {
     const { betterer } = await import('@betterer/betterer');
 
-    const fixture = await createFixture('coverage-total', {
+    const { paths, logs, cleanup, resolve, readFile, testNames, writeFile } = await createFixture('coverage-total', {
       '.betterer.js': `
 import { coverageTotal } from '@betterer/coverage';
 
 export default {
-  test: () => coverageTotal()
+  test: () => coverageTotal('./my-report/coverage.json')
 };    
         `,
       'tsconfig.json': `
@@ -22,65 +22,110 @@ export default {
       `
     });
 
-    const coverage = `{  
+    const file1Path = resolve('./src/file-1.ts');
+    const file2Path = resolve('./src/file-2.ts');
+
+    const coverage = `
+{
   "total": {
     "lines": { "total": 220, "covered": 110, "skipped": 0, "pct": 50 },
     "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
     "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
     "branches": { "total": 300, "covered": 100, "skipped": 0, "pct": 33.3 }
+  },
+  "${file1Path}": {
+    "lines": { "total": 100, "covered": 50, "skipped": 0, "pct": 50 },
+    "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
+    "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  },
+  "${file2Path}": {
+    "lines": { "total": 120, "covered": 60, "skipped": 0, "pct": 50 },
+    "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
+    "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
   }
-}`;
+}
+    `;
 
-    const configPaths = [fixture.paths.config];
-    const resultsPath = fixture.paths.results;
-    const coveragePath = fixture.resolve('./coverage/coverage-summary.json');
+    const configPaths = [paths.config];
+    const resultsPath = paths.results;
+    const coveragePath = resolve('./my-report/coverage.json');
 
-    await fixture.writeFile(coveragePath, coverage);
+    await writeFile(coveragePath, coverage);
 
     const newTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(newTestRun.new)).toEqual(['test']);
+    expect(testNames(newTestRun.new)).toEqual(['test']);
 
-    const result = await fixture.readFile(resultsPath);
+    const result = await readFile(resultsPath);
 
     expect(result).toMatchSnapshot();
 
     const sameTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(sameTestRun.same)).toEqual(['test']);
+    expect(testNames(sameTestRun.same)).toEqual(['test']);
 
-    const betterCoverage = `{  
-      "total": {
-        "lines": { "total": 220, "covered": 210, "skipped": 0, "pct": 95.4 },
-        "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
-        "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
-        "branches": { "total": 300, "covered": 100, "skipped": 0, "pct": 33.3 }
-      }
-    }`;
+    const betterCoverage = `
+{
+  "total": {
+    "lines": { "total": 220, "covered": 210, "skipped": 0, "pct": 95.4 },
+    "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
+    "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
+    "branches": { "total": 300, "covered": 100, "skipped": 0, "pct": 33.3 }
+  },
+  "${file1Path}": {
+    "lines": { "total": 100, "covered": 100, "skipped": 0, "pct": 100 },
+    "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
+    "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  },
+  "${file2Path}": {
+    "lines": { "total": 120, "covered": 110, "skipped": 0, "pct": 91.6 },
+    "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
+    "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  }
+}
+    `;
 
-    await fixture.writeFile(coveragePath, betterCoverage);
+    await writeFile(coveragePath, betterCoverage);
 
     const betterTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(betterTestRun.better)).toEqual(['test']);
+    expect(testNames(betterTestRun.better)).toEqual(['test']);
 
-    const worseCoverage = `{  
-      "total": {
-        "lines": { "total": 220, "covered": 210, "skipped": 0, "pct": 95.4 },
-        "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
-        "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
-        "branches": { "total": 300, "covered":90, "skipped": 0, "pct": 30 }
-      }
-    }`;
+    const worseCoverage = `
+{
+  "total": {
+    "lines": { "total": 220, "covered": 210, "skipped": 0, "pct": 95.4 },
+    "statements": { "total": 410, "covered": 140, "skipped": 0, "pct": 34.1 },
+    "functions": { "total": 30, "covered": 11, "skipped": 0, "pct": 36.6 },
+    "branches": { "total": 300, "covered": 90, "skipped": 0, "pct": 30 }
+  },
+  "${file1Path}": {
+    "lines": { "total": 100, "covered": 100, "skipped": 0, "pct": 100 },
+    "statements": { "total": 200, "covered": 70, "skipped": 0, "pct": 35 },
+    "functions": { "total": 20, "covered": 5, "skipped": 0, "pct": 25 },
+    "branches": { "total": 150, "covered": 40, "skipped": 0, "pct": 26.6 }
+  },
+  "${file2Path}": {
+    "lines": { "total": 120, "covered": 110, "skipped": 0, "pct": 91.6 },
+    "statements": { "total": 210, "covered": 70, "skipped": 0, "pct": 33.3 },
+    "functions": { "total": 10, "covered": 6, "skipped": 0, "pct": 60 },
+    "branches": { "total": 150, "covered": 50, "skipped": 0, "pct": 33.3 }
+  }
+}
+    `;
 
-    await fixture.writeFile(coveragePath, worseCoverage);
+    await writeFile(coveragePath, worseCoverage);
 
     const worseTestRun = await betterer({ configPaths, resultsPath, workers: false });
 
-    expect(fixture.testNames(worseTestRun.worse)).toEqual(['test']);
+    expect(testNames(worseTestRun.worse)).toEqual(['test']);
 
-    expect(fixture.logs).toMatchSnapshot();
+    expect(logs).toMatchSnapshot();
 
-    await fixture.cleanup();
+    await cleanup();
   });
 });
diff --git a/website/docs/coverage-test.md b/website/docs/coverage-test.md
index ed2870fc3..18502ef8f 100644
--- a/website/docs/coverage-test.md
+++ b/website/docs/coverage-test.md
@@ -10,22 +10,29 @@ slug: /coverage-test
 
 Use the `coverage` test to incrementally increase the per-file test coverage of your project.
 
+:::caution
+
 [`@betterer/coverage`](https://www.npmjs.com/package/@betterer/coverage) expects an [Istanbul](https://istanbul.js.org/) [json-summary](https://github.com/istanbuljs/istanbuljs/tree/master/packages/istanbul-reports/lib/json-summary) to exist, so you must run your tests first.
+:::
+
+By default, `coverage()` looks for the summary at `'./coverage/coverage-summary.json'`, but you can pass the path to wherever yours is located, relative to your [test definition file](./test-definition-file).
 
 ```typescript
 import { coverage } from '@betterer/coverage';
 
 export default {
-  'increase per-file test coverage': () => coverage()
+  'increase per-file test coverage': () => coverage('./my-reports/coverage.json')
 };
 ```
 
 Use the `coverageTotal` test to incrementally increase the total test coverage of your project.
 
-```javascript
+```typescript
 import { coverageTotal } from '@betterer/coverage';
 
 export default {
   'increase total test coverage': () => coverageTotal()
 };
 ```
+
+[`@betterer/coverage`](https://www.npmjs.com/package/@betterer/coverage) is a [BettererResolverTest](./betterer.bettererresolvertest), so you can use [`include`](./betterer.bettererresolvertest.include), [`exclude`](./betterer.bettererresolvertest.exclude), [`only`](betterer.bettererresolvertest.only), and [`skip`](betterer.bettererresolvertest.skip).