feat(@angular/build): add code coverage reporters option for unit-test

The experimental `unit-test` builder now contains an additional option
named `codeCoverageReporters` that supports configuring the reporter(s)
for code coverage results. This options only has an effect if the `codeCoverage`
option is also enabled.  The `codeCoverageReporters` is an array with
elements that can be either a string or a tuple of a string and options
object. The later form supports customizing individual reporters. The
options object fields are not validated by the builder schema.
This option currently only is used by the `vitest` runner.
Currently supported values for a coverage reporter are:
"html", "lcov", "lcovonly", "text", "text-summary", "cobertura"

Author: clydin

packages/angular/build/src/builders/unit-test/builder.ts

@@ -237,7 +237,8 @@ export async function* execute(
             browser,
             reporters: normalizedOptions.reporters ?? ['default'],
             coverage: {
-              enabled: normalizedOptions.codeCoverage,
+              enabled: !!normalizedOptions.codeCoverage,
+              reporter: normalizedOptions.codeCoverage?.reporters,
               excludeAfterRemap: true,
             },
             ...debugOptions,
@@ -251,7 +252,7 @@ export async function* execute(
                 // builder's test setup. To workaround this, the excludes are adjusted here to only automatically
                 // exclude the TypeScript source test files.
                 context.project.config.coverage.exclude = [
-                  ...(normalizedOptions.codeCoverageExclude ?? []),
+                  ...(normalizedOptions.codeCoverage?.exclude ?? []),
                   '**/*.{test,spec}.?(c|m)ts',
                 ];
               },

packages/angular/build/src/builders/unit-test/karma-bridge.ts

@@ -45,8 +45,8 @@ export async function useKarmaBuilder(
     poll: buildTargetOptions.poll,
     preserveSymlinks: buildTargetOptions.preserveSymlinks,
     browsers: unitTestOptions.browsers?.join(','),
-    codeCoverage: unitTestOptions.codeCoverage,
-    codeCoverageExclude: unitTestOptions.codeCoverageExclude,
+    codeCoverage: !!unitTestOptions.codeCoverage,
+    codeCoverageExclude: unitTestOptions.codeCoverage?.exclude,
     fileReplacements: buildTargetOptions.fileReplacements,
     reporters: unitTestOptions.reporters,
     webWorkerTsConfig: buildTargetOptions.webWorkerTsConfig,

packages/angular/build/src/builders/unit-test/options.ts

@@ -33,7 +33,7 @@ export async function normalizeOptions(
   const buildTargetSpecifier = options.buildTarget ?? `::development`;
   const buildTarget = targetFromTargetString(buildTargetSpecifier, projectName, 'build');
 
-  const { codeCoverage, codeCoverageExclude, tsConfig, runner, reporters, browsers } = options;
+  const { tsConfig, runner, reporters, browsers } = options;
 
   return {
     // Project/workspace information
@@ -46,8 +46,16 @@ export async function normalizeOptions(
     include: options.include ?? ['**/*.spec.ts'],
     exclude: options.exclude ?? [],
     runnerName: runner,
-    codeCoverage,
-    codeCoverageExclude,
+    codeCoverage: options.codeCoverage
+      ? {
+          exclude: options.codeCoverageExclude,
+          reporters: options.codeCoverageReporters?.map((entry) =>
+            typeof entry === 'string'
+              ? ([entry, {}] as [string, Record<string, unknown>])
+              : (entry as [string, Record<string, unknown>]),
+          ),
+        }
+      : undefined,
     tsConfig,
     reporters,
     browsers,

packages/angular/build/src/builders/unit-test/schema.json

@@ -64,6 +64,23 @@
       },
       "default": []
     },
+    "codeCoverageReporters": {
+      "type": "array",
+      "description": "Reporters to use for code coverage results.",
+      "items": {
+        "oneOf": [
+          {
+            "$ref": "#/definitions/coverage-reporters"
+          },
+          {
+            "type": "array",
+            "minItems": 1,
+            "maxItems": 2,
+            "items": [{ "$ref": "#/definitions/coverage-reporters" }, { "type": "object" }]
+          }
+        ]
+      }
+    },
     "reporters": {
       "type": "array",
       "description": "Test runner reporters to use. Directly passed to the test runner.",
@@ -78,5 +95,10 @@
     }
   },
   "additionalProperties": false,
-  "required": ["buildTarget", "tsConfig", "runner"]
+  "required": ["buildTarget", "tsConfig", "runner"],
+  "definitions": {
+    "coverage-reporters": {
+      "enum": ["html", "lcov", "lcovonly", "text", "text-summary", "cobertura"]
+    }
+  }
 }