fix(@angular-devkit/build-angular): do not fail compilation when spec pattern does not match

Previously, we failed the compilation when the specified patterns did not match any spec file. This breaks the case were users configure Karma to not fail on empty test suit.

Closes #24644

(cherry picked from commit d9c697b)

Author: alan-agius4

packages/angular_devkit/build_angular/src/builders/karma/find-tests-plugin.ts

@@ -9,10 +9,10 @@
 import assert from 'assert';
 import { PathLike, constants, promises as fs } from 'fs';
 import glob, { hasMagic } from 'glob';
+import { pluginName } from 'mini-css-extract-plugin';
 import { basename, dirname, extname, join, relative } from 'path';
 import { promisify } from 'util';
 import type { Compilation, Compiler } from 'webpack';
-import { addError } from '../../utils/webpack-diagnostics';
 
 const globPromise = promisify(glob);
 
@@ -49,23 +49,21 @@ export class FindTestsPlugin {
     // Add tests files are part of the entry-point.
     webpackOptions.entry = async () => {
       const specFiles = await findTests(include, exclude, workspaceRoot, projectSourceRoot);
-
-      if (!specFiles.length) {
-        assert(this.compilation, 'Compilation cannot be undefined.');
-        addError(
-          this.compilation,
-          `Specified patterns: "${include.join(', ')}" did not match any spec files.`,
-        );
-      }
-
       const entrypoints = await entry;
       const entrypoint = entrypoints['main'];
       if (!entrypoint.import) {
         throw new Error(`Cannot find 'main' entrypoint.`);
       }
 
-      originalImport ??= entrypoint.import;
-      entrypoint.import = [...originalImport, ...specFiles];
+      if (specFiles.length) {
+        originalImport ??= entrypoint.import;
+        entrypoint.import = [...originalImport, ...specFiles];
+      } else {
+        assert(this.compilation, 'Compilation cannot be undefined.');
+        this.compilation
+          .getLogger(pluginName)
+          .error(`Specified patterns: "${include.join(', ')}" did not match any spec files.`);
+      }
 
       return entrypoints;
     };

packages/angular_devkit/build_angular/src/builders/karma/tests/options/include_spec.ts

@@ -17,16 +17,8 @@ describeBuilder(execute, KARMA_BUILDER_INFO, (harness) => {
         include: ['abc.spec.ts', 'def.spec.ts'],
       });
 
-      const { result, logs } = await harness.executeOnce();
+      const { result } = await harness.executeOnce();
       expect(result?.success).toBeFalse();
-      expect(logs).toContain(
-        jasmine.objectContaining({
-          level: 'error',
-          message: jasmine.stringContaining(
-            'Specified patterns: "abc.spec.ts, def.spec.ts" did not match any spec files.',
-          ),
-        }),
-      );
     });
 
     [