build: fix material unit tests not running (#7117)

Author: jelbourn

tools/package-tools/build-package.ts

@@ -3,6 +3,7 @@ import {spawn} from 'child_process';
 import {readFileSync, writeFileSync} from 'fs';
 import {sync as glob} from 'glob';
 import {join} from 'path';
+import {main as ngc} from '@angular/tsc-wrapped';
 import {PackageBundler} from './build-bundles';
 import {buildConfig} from './build-config';
 import {getSecondaryEntryPointsForPackage} from './secondary-entry-points';
@@ -82,7 +83,7 @@ export class BuildPackage {
 
   /** Compiles the TypeScript test source files for the package. */
   async compileTests() {
-    await this._compileEntryPoint(testsTsconfigName);
+    await this._compileTestEntryPoint(testsTsconfigName);
   }
 
   /** Creates all bundles for the package and all associated entry points. */
@@ -108,6 +109,15 @@ export class BuildPackage {
     .then(() => this.renamePrivateReExportsToBeUnique(secondaryEntryPoint));
   }
 
+  /** Compiles the TypeScript sources of a primary or secondary entry point. */
+  private async _compileTestEntryPoint(tsconfigName: string, secondaryEntryPoint = '') {
+    const entryPointPath = join(this.sourceDir, secondaryEntryPoint);
+    const entryPointTsconfigPath = join(entryPointPath, tsconfigName);
+
+    await ngc(entryPointTsconfigPath, {basePath: entryPointPath});
+    this.renamePrivateReExportsToBeUnique(secondaryEntryPoint);
+  }
+
   /** Renames `ɵa`-style re-exports generated by Angular to be unique across compilation units. */
   private renamePrivateReExportsToBeUnique(secondaryEntryPoint = '') {
     // When we compiled the typescript sources with ngc, we do entry-point individually.