Ci coverage (#5)

* ci: Add code coverage script

.github/workflows/deno.yml

@@ -8,14 +8,17 @@ on:
 
 jobs:
   deno:
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
 
     steps:
       - name: Setup repo
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setup Deno
-        run: brew install deno
+        run: sudo snap install deno
 
       - name: Run tests
         run: deno fmt --check && deno lint && deno test --allow-net --parallel tests/
+
+      - name: Check coverage
+        run: deno run -A scripts/coverage.ts

.gitignore

@@ -1,5 +1,3 @@
 .DS_Store
-.coverage
-lcov.info
-staging/
+coverage/
 .env

scripts/coverage.ts

@@ -0,0 +1,66 @@
+/**
+ * Calculates and checks the branch coverage of a Deno project.
+ *
+ * @remarks
+ * This script runs the tests with coverage enabled and then analyzes the coverage results.
+ * If the branch coverage is below a specified threshold, it exits with an error.
+ *
+ * @param THRESHOLD - The minimum branch coverage threshold (in percentage) required for the project.
+ */
+
+// Minimum branch coverage threshold (in percentage)
+const THRESHOLD = 90;
+
+const getCommandOutput = async (command: Deno.Command) => {
+  const { code, stdout, stderr } = await command.output();
+  const error = new TextDecoder().decode(stderr);
+  if (code || error) {
+    console.error(error);
+    Deno.exit(1);
+  }
+  const output = new TextDecoder().decode(stdout);
+  return output;
+};
+
+// Run tests with coverage enabled
+const testCmd = new Deno.Command(Deno.execPath(), {
+  args: [
+    "test",
+    "--coverage",
+  ],
+});
+
+// Check that the command ran successfully
+await getCommandOutput(testCmd);
+
+// Calculate branch coverage
+const covCmd = new Deno.Command(Deno.execPath(), {
+  args: [
+    "coverage",
+    "./coverage",
+  ],
+});
+
+// Check that the command ran successfully
+const coverageReport = await getCommandOutput(covCmd);
+
+// Remove ANSI escape codes
+const words = coverageReport.replaceAll("\x1b", " ").split(" ");
+
+// Remove all non-numbers
+const floats = words.filter((word) => !isNaN(parseFloat(word)));
+
+// Pick the second last number
+const branchTotal = parseFloat(floats.at(-2) || "");
+
+if (!branchTotal) {
+  console.error("Could not retrieve branch coverage");
+  Deno.exit(1);
+}
+
+if (branchTotal > THRESHOLD) {
+  console.log(`Branch coverage is good: ${branchTotal}`);
+} else {
+  console.log(`Branch coverage is bad: ${branchTotal}`);
+  Deno.exit(1);
+}