Add functions to help test results

aoc/Cargo.toml

@@ -12,6 +12,7 @@ color-eyre = "0.6.2"
 eyre = "0.6.8"
 itertools = "0.11.0"
 lazy_static = "1.4.0"
+mktemp = "0.5.1"
 thiserror = "1.0.48"
 
 [dev-dependencies]

aoc/src/lib.rs

@@ -7,6 +7,7 @@ pub mod error;
 pub mod input;
 mod run;
 mod runners;
+pub mod test;
 
 pub use run::run;
 pub use runners::register_runner;

aoc/src/test.rs

@@ -0,0 +1,59 @@
+use eyre::{bail, Context};
+use std::path::Path;
+use std::process::Command;
+
+const ENV_VAR: &str = "RECORD_RESULTS";
+
+fn run_with(args: &[&str]) -> eyre::Result<String> {
+    let output = Command::new("cargo")
+        .args(["run", "--release", "--", "-a"])
+        .args(args)
+        .output()?;
+    Ok(String::from_utf8(output.stdout)?)
+}
+
+fn equal_content<P: AsRef<Path>>(actual: &str, expected: P, show_diff: bool) -> eyre::Result<bool> {
+    let expected_content = std::fs::read_to_string(expected.as_ref()).context(format!(
+        "cannot read {}",
+        expected.as_ref().to_string_lossy()
+    ))?;
+    if actual == expected_content {
+        Ok(true)
+    } else {
+        if show_diff {
+            let temp = mktemp::Temp::new_file()?;
+            std::fs::write(&temp, actual)?;
+            let diff = Command::new("diff")
+                .arg("-u")
+                .arg(expected.as_ref())
+                .arg(temp.as_path())
+                .output()?;
+            if !diff.stderr.is_empty() {
+                bail!(String::from_utf8(diff.stderr)?);
+            }
+            println!(
+                "Actual does not meet expected:\n{}",
+                String::from_utf8(diff.stdout)?
+            );
+            println!("\nRe-run with {ENV_VAR}=1 to update reference files");
+        }
+        Ok(false)
+    }
+}
+
+pub fn check_results<P: AsRef<Path>>(expected: P, main_only: bool) -> eyre::Result<bool> {
+    let actual = if main_only {
+        run_with(&["-m"])?
+    } else {
+        run_with(&[])?
+    };
+    let update = std::env::var(ENV_VAR).is_ok();
+    if update {
+        if !matches!(equal_content(&actual, &expected, false), Ok(true)) {
+            std::fs::write(expected, actual)?;
+        }
+        Ok(true)
+    } else {
+        equal_content(&actual, &expected, !update)
+    }
+}

aoc/tests/dummy-year.rs

@@ -65,3 +65,21 @@ fn all_days_main() {
     Day 2 - part 2: 3842356
     "###);
 }
+
+#[test]
+#[serial]
+fn check_expected_main() {
+    let dir = std::env::current_dir().unwrap();
+    std::env::set_current_dir("../dummy-year").unwrap();
+    assert!(aoc::test::check_results("expected.txt", true).unwrap());
+    std::env::set_current_dir(dir).unwrap();
+}
+
+#[test]
+#[serial]
+fn check_expected() {
+    let dir = std::env::current_dir().unwrap();
+    std::env::set_current_dir("../dummy-year").unwrap();
+    assert!(aoc::test::check_results("expected-all.txt", false).unwrap());
+    std::env::set_current_dir(dir).unwrap();
+}

dummy-year/expected-all.txt

@@ -0,0 +1,7 @@
+Day 1 - part 1: 232
+Day 1 - part 1 — str_slice: 232
+Day 1 - part 2: 1783
+Day 1 - part 2 — result: 1783
+Day 1 - part 2 — result_string: 1783
+Day 2 - part 1: 1606483
+Day 2 - part 2: 3842356

dummy-year/expected.txt

@@ -0,0 +1,4 @@
+Day 1 - part 1: 232
+Day 1 - part 2: 1783
+Day 2 - part 1: 1606483
+Day 2 - part 2: 3842356