test(@angular-devkit/build-angular): add support for builder harness directory expectations

When using the builder harness in unit tests, expectations can now be made directly for
directories. Currently the existence, or lack thereof, can be tested using the harness.
This is similar to be existing file expectations. More capability may be added as needed
in the future.

Author: clydin

packages/angular_devkit/build_angular/src/testing/builder-harness.ts

@@ -22,7 +22,7 @@ import {
 import { WorkspaceHost } from '@angular-devkit/architect/node';
 import { TestProjectHost } from '@angular-devkit/architect/testing';
 import { getSystemPath, json, logging } from '@angular-devkit/core';
-import { existsSync, readFileSync, readdirSync } from 'node:fs';
+import { existsSync, readFileSync, readdirSync, statSync } from 'node:fs';
 import fs from 'node:fs/promises';
 import { dirname, join } from 'node:path';
 import {
@@ -351,6 +351,12 @@ export class BuilderHarness<T> {
     return existsSync(fullPath);
   }
 
+  hasDirectory(path: string): boolean {
+    const fullPath = this.resolvePath(path);
+
+    return statSync(fullPath, { throwIfNoEntry: false })?.isDirectory() ?? false;
+  }
+
   hasFileMatch(directory: string, pattern: RegExp): boolean {
     const fullPath = this.resolvePath(directory);
 

packages/angular_devkit/build_angular/src/testing/jasmine-helpers.ts

@@ -42,6 +42,9 @@ export class JasmineBuilderHarness<T> extends BuilderHarness<T> {
   expectFile(path: string): HarnessFileMatchers {
     return expectFile(path, this);
   }
+  expectDirectory(path: string): HarnessDirectoryMatchers {
+    return expectDirectory(path, this);
+  }
 }
 
 export interface HarnessFileMatchers {
@@ -51,6 +54,11 @@ export interface HarnessFileMatchers {
   readonly size: jasmine.Matchers<number>;
 }
 
+export interface HarnessDirectoryMatchers {
+  toExist(): boolean;
+  toNotExist(): boolean;
+}
+
 /**
  * Add a Jasmine expectation filter to an expectation that always fails with a message.
  * @param base The base expectation (`expect(...)`) to use.
@@ -125,3 +133,23 @@ export function expectFile<T>(path: string, harness: BuilderHarness<T>): Harness
     },
   };
 }
+
+export function expectDirectory<T>(
+  path: string,
+  harness: BuilderHarness<T>,
+): HarnessDirectoryMatchers {
+  return {
+    toExist() {
+      const exists = harness.hasDirectory(path);
+      expect(exists).toBe(true, 'Expected directory to exist: ' + path);
+
+      return exists;
+    },
+    toNotExist() {
+      const exists = harness.hasDirectory(path);
+      expect(exists).toBe(false, 'Expected directory to not exist: ' + path);
+
+      return !exists;
+    },
+  };
+}