add ci README

ci/README.md

@@ -0,0 +1,49 @@
+# Basemaps Visual Test Suite
+
+## Artifacts
+
+Recent git commits on `main` and pull requests each have a set of artifacts.
+
+The test suite depends on the existence of a public HTTP endpoint with these paths:
+
+* `ci-storage.protomaps.com/smalltestregion.osm.pbf`
+* `ci-storage.protomaps.com/artifacts/ARTIFACT_SHA/smalltestregion_vector.pmtiles`
+* `ci-storage.protomaps.com/artifacts/ARTIFACT_SHA/light.json`
+
+`smalltestregion_vector.pmtiles` is the java tiler output at SHA run on `smalltestregion.osm.pbf`.
+`light.json` is the generated `layers` of the GL JSON (not the full style).
+
+*Later we will add more than just light.json*
+
+## Test Examples
+
+The file `examples.json` is a JSON array of named examples. Each example consists of:
+
+* a `center` lon,lat
+* a `zoom` level
+* a `name` that must be a simple slug e.g. `null-island`
+* a `description` to explain the cartographic feature under test.
+* an array of string `tags` that group examples e.g. `buildings`, `national-parks`
+
+## Test Runner
+
+`index.html` is the single-file test runner, there is no build step. It takes query parameters:
+
+Required query parameters:
+
+* `?left=abc123&right=61`: The Artifact SHA or PR# to display on each side of the comparison.
+
+Optional query parameters:
+
+* `?name=null-island`: run only the named example.
+* `?tag=national-parks`: run only one tag.
+* `?showDifferencesOnly`: run the tests, but only display where the pixels don't match.
+
+## Versions
+
+The tile archive and named style layers are the only versioned artifacts. Non-versioned parts that affect the test run:
+
+* The current `examples.json`
+* The `smalltestregion.osm.pbf` covered areas and snapshot date from OSM.
+* The `maplibre-gl-js` version.
+* The font glyphs and sprite assets used by the style.

ci/examples.json

@@ -1,15 +1,15 @@
 [
   {
-    "name":"oakland-ca-road-network",
+    "name":"taiwan-z8",
     "description":"Compare the appearance of highways",
-    "tags":["highway"],
+    "tags":["highway", "cjk"],
     "center":[121.333,24.320],
     "zoom":8
   },
   {
-    "name":"jakarta-buildings",
+    "name":"taiwan-z16-buildings",
     "description":"Compare the appearance of buildings",
-    "tags":["buildings","indonesia"],
+    "tags":["buildings","cjk"],
     "center":[121.4818, 25.0271],
     "zoom": 16
   }