test(ivy): introduce route testing mode for ngtsc tests (#27697)

This commit introduces a new mode for the NgtscTestEnvironment which
builds the NgtscProgram and then asks for the list of lazy routes,
instead of running the TS emit phase.

PR Close #27697

packages/compiler-cli/src/main.ts

@@ -115,7 +115,7 @@ function createEmitCallback(options: api.CompilerOptions): api.TsEmitCallback|un
 
 export interface NgcParsedConfiguration extends ParsedConfiguration { watch?: boolean; }
 
-function readNgcCommandLineAndConfiguration(args: string[]): NgcParsedConfiguration {
+export function readNgcCommandLineAndConfiguration(args: string[]): NgcParsedConfiguration {
   const options: api.CompilerOptions = {};
   const parsedArgs = require('minimist')(args);
   if (parsedArgs.i18nFile) options.i18nInFile = parsedArgs.i18nFile;

packages/compiler-cli/test/ngtsc/BUILD.bazel

@@ -7,6 +7,7 @@ ts_library(
     deps = [
         "//packages/compiler",
         "//packages/compiler-cli",
+        "//packages/compiler-cli/src/ngtsc/routing",
         "//packages/compiler-cli/test:test_utils",
         "@ngdeps//typescript",
     ],

packages/compiler-cli/test/ngtsc/env.ts

@@ -11,7 +11,9 @@ import * as fs from 'fs';
 import * as path from 'path';
 import * as ts from 'typescript';
 
-import {main, mainDiagnosticsForTest} from '../../src/main';
+import {createCompilerHost, createProgram} from '../../ngtools2';
+import {main, mainDiagnosticsForTest, readNgcCommandLineAndConfiguration} from '../../src/main';
+import {LazyRoute} from '../../src/ngtsc/routing';
 import {TestSupport, isInBazel, setup} from '../test_support';
 
 function setupFakeCore(support: TestSupport): void {
@@ -127,5 +129,12 @@ export class NgtscTestEnvironment {
     return mainDiagnosticsForTest(['-p', this.basePath]) as ReadonlyArray<ts.Diagnostic>;
   }
 
+  driveRoutes(entryPoint?: string): LazyRoute[] {
+    const {rootNames, options} = readNgcCommandLineAndConfiguration(['-p', this.basePath]);
+    const host = createCompilerHost({options});
+    const program = createProgram({rootNames, host, options});
+    return program.listLazyRoutes(entryPoint);
+  }
+
   static get supported(): boolean { return isInBazel(); }
 }