diff --git a/packages/language-service/ivy/test/diagnostic_spec.ts b/packages/language-service/ivy/test/diagnostic_spec.ts
new file mode 100644
index 0000000000..0031673450
--- /dev/null
+++ b/packages/language-service/ivy/test/diagnostic_spec.ts
@@ -0,0 +1,108 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {absoluteFrom} from '@angular/compiler-cli/src/ngtsc/file_system';
+import {initMockFileSystem} from '@angular/compiler-cli/src/ngtsc/file_system/testing';
+import {LanguageServiceTestEnvironment} from '@angular/language-service/ivy/test/env';
+import * as ts from 'typescript';
+import {createModuleWithDeclarations} from './test_utils';
+
+describe('getSemanticDiagnostics', () => {
+  let env: LanguageServiceTestEnvironment;
+
+  beforeEach(() => {
+    initMockFileSystem('Native');
+  });
+
+  it('should not produce error for a minimal component defintion', () => {
+    const appFile = {
+      name: absoluteFrom('/app.ts'),
+      contents: `
+      import {Component, NgModule} from '@angular/core';
+
+      @Component({
+        template: ''
+      })
+      export class AppComponent {}
+    `
+    };
+    env = createModuleWithDeclarations([appFile]);
+
+    const diags = env.ngLS.getSemanticDiagnostics(absoluteFrom('/app.ts'));
+    expect(diags.length).toEqual(0);
+  });
+
+  it('should report member does not exist', () => {
+    const appFile = {
+      name: absoluteFrom('/app.ts'),
+      contents: `
+      import {Component, NgModule} from '@angular/core';
+
+      @Component({
+        template: '{{nope}}'
+      })
+      export class AppComponent {}
+    `
+    };
+    env = createModuleWithDeclarations([appFile]);
+
+    const diags = env.ngLS.getSemanticDiagnostics(absoluteFrom('/app.ts'));
+    expect(diags.length).toBe(1);
+    const {category, file, start, length, messageText} = diags[0];
+    expect(category).toBe(ts.DiagnosticCategory.Error);
+    expect(file?.fileName).toBe('/app.ts');
+    expect(messageText).toBe(`Property 'nope' does not exist on type 'AppComponent'.`);
+  });
+
+  it('should process external template', () => {
+    const appFile = {
+      name: absoluteFrom('/app.ts'),
+      contents: `
+      import {Component, NgModule} from '@angular/core';
+
+      @Component({
+        templateUrl: './app.html'
+      })
+      export class AppComponent {}
+    `
+    };
+    const templateFile = {
+      name: absoluteFrom('/app.html'),
+      contents: `
+      Hello world!
+    `
+    };
+
+    env = createModuleWithDeclarations([appFile], [templateFile]);
+    const diags = env.ngLS.getSemanticDiagnostics(absoluteFrom('/app.html'));
+    expect(diags).toEqual([]);
+  });
+
+  it('should report member does not exist in external template', () => {
+    const appFile = {
+      name: absoluteFrom('/app.ts'),
+      contents: `
+      import {Component, NgModule} from '@angular/core';
+
+      @Component({
+        templateUrl: './app.html'
+      })
+      export class AppComponent {}
+    `
+    };
+    const templateFile = {name: absoluteFrom('/app.html'), contents: `{{nope}}`};
+
+    env = createModuleWithDeclarations([appFile], [templateFile]);
+    const diags = env.ngLS.getSemanticDiagnostics(absoluteFrom('/app.html'));
+    expect(diags.length).toBe(1);
+    const {category, file, start, length, messageText} = diags[0];
+    expect(category).toBe(ts.DiagnosticCategory.Error);
+    expect(file?.fileName).toBe('/app.html');
+    expect(messageText).toBe(`Property 'nope' does not exist on type 'AppComponent'.`);
+  });
+});
diff --git a/packages/language-service/ivy/test/legacy/daignostic_spec.ts b/packages/language-service/ivy/test/legacy/daignostic_spec.ts
new file mode 100644
index 0000000000..f3da97fc39
--- /dev/null
+++ b/packages/language-service/ivy/test/legacy/daignostic_spec.ts
@@ -0,0 +1,41 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {LanguageService} from '../../language_service';
+
+import {MockService, setup, TEST_TEMPLATE} from './mock_host';
+
+describe('getSemanticDiagnostics', () => {
+  let service: MockService;
+  let ngLS: LanguageService;
+
+  beforeAll(() => {
+    const {project, service: _service, tsLS} = setup();
+    service = _service;
+    ngLS = new LanguageService(project, tsLS);
+  });
+
+  beforeEach(() => {
+    service.reset();
+  });
+
+  it('should retrieve external template from latest snapshot', () => {
+    // This test is to make sure we are reading from snapshot instead of disk
+    // if content from snapshot is newer. It also makes sure the internal cache
+    // of the resource loader is invalidated on content change.
+    service.overwrite(TEST_TEMPLATE, `{{ foo }}`);
+    const d1 = ngLS.getSemanticDiagnostics(TEST_TEMPLATE);
+    expect(d1.length).toBe(1);
+    expect(d1[0].messageText).toBe(`Property 'foo' does not exist on type 'TemplateReference'.`);
+
+    service.overwrite(TEST_TEMPLATE, `{{ bar }}`);
+    const d2 = ngLS.getSemanticDiagnostics(TEST_TEMPLATE);
+    expect(d2.length).toBe(1);
+    expect(d2[0].messageText).toBe(`Property 'bar' does not exist on type 'TemplateReference'.`);
+  });
+});
diff --git a/packages/language-service/ivy/test/legacy/diagnostic_spec.ts b/packages/language-service/ivy/test/legacy/diagnostic_spec.ts
deleted file mode 100644
index 1d8f6c4ef3..0000000000
--- a/packages/language-service/ivy/test/legacy/diagnostic_spec.ts
+++ /dev/null
@@ -1,75 +0,0 @@
-/**
- * @license
- * Copyright Google LLC All Rights Reserved.
- *
- * Use of this source code is governed by an MIT-style license that can be
- * found in the LICENSE file at https://angular.io/license
- */
-
-import * as ts from 'typescript/lib/tsserverlibrary';
-
-import {LanguageService} from '../../language_service';
-
-import {APP_COMPONENT, MockService, setup, TEST_TEMPLATE} from './mock_host';
-
-describe('getSemanticDiagnostics', () => {
-  let service: MockService;
-  let ngLS: LanguageService;
-
-  beforeAll(() => {
-    const {project, service: _service, tsLS} = setup();
-    service = _service;
-    ngLS = new LanguageService(project, tsLS);
-  });
-
-  beforeEach(() => {
-    service.reset();
-  });
-
-  it('should not produce error for AppComponent', () => {
-    const diags = ngLS.getSemanticDiagnostics(APP_COMPONENT);
-    expect(diags).toEqual([]);
-  });
-
-  it('should report member does not exist', () => {
-    const {text} = service.overwriteInlineTemplate(APP_COMPONENT, '{{ nope }}');
-    const diags = ngLS.getSemanticDiagnostics(APP_COMPONENT);
-    expect(diags.length).toBe(1);
-    const {category, file, start, length, messageText} = diags[0];
-    expect(category).toBe(ts.DiagnosticCategory.Error);
-    expect(file?.fileName).toBe(APP_COMPONENT);
-    expect(text.substring(start!, start! + length!)).toBe('nope');
-    expect(messageText).toBe(`Property 'nope' does not exist on type 'AppComponent'.`);
-  });
-
-  it('should process external template', () => {
-    const diags = ngLS.getSemanticDiagnostics(TEST_TEMPLATE);
-    expect(diags).toEqual([]);
-  });
-
-  it('should report member does not exist in external template', () => {
-    const {text} = service.overwrite(TEST_TEMPLATE, `{{ nope }}`);
-    const diags = ngLS.getSemanticDiagnostics(TEST_TEMPLATE);
-    expect(diags.length).toBe(1);
-    const {category, file, start, length, messageText} = diags[0];
-    expect(category).toBe(ts.DiagnosticCategory.Error);
-    expect(file?.fileName).toBe(TEST_TEMPLATE);
-    expect(text.substring(start!, start! + length!)).toBe('nope');
-    expect(messageText).toBe(`Property 'nope' does not exist on type 'TemplateReference'.`);
-  });
-
-  it('should retrieve external template from latest snapshot', () => {
-    // This test is to make sure we are reading from snapshot instead of disk
-    // if content from snapshot is newer. It also makes sure the internal cache
-    // of the resource loader is invalidated on content change.
-    service.overwrite(TEST_TEMPLATE, `{{ foo }}`);
-    const d1 = ngLS.getSemanticDiagnostics(TEST_TEMPLATE);
-    expect(d1.length).toBe(1);
-    expect(d1[0].messageText).toBe(`Property 'foo' does not exist on type 'TemplateReference'.`);
-
-    service.overwrite(TEST_TEMPLATE, `{{ bar }}`);
-    const d2 = ngLS.getSemanticDiagnostics(TEST_TEMPLATE);
-    expect(d2.length).toBe(1);
-    expect(d2[0].messageText).toBe(`Property 'bar' does not exist on type 'TemplateReference'.`);
-  });
-});
diff --git a/packages/language-service/ivy/test/references_spec.ts b/packages/language-service/ivy/test/references_spec.ts
index 249f305cb9..b56e3ca8ff 100644
--- a/packages/language-service/ivy/test/references_spec.ts
+++ b/packages/language-service/ivy/test/references_spec.ts
@@ -11,7 +11,7 @@ import {initMockFileSystem, TestFile} from '@angular/compiler-cli/src/ngtsc/file
 import * as ts from 'typescript/lib/tsserverlibrary';
 
 import {extractCursorInfo, LanguageServiceTestEnvironment} from './env';
-import {getText} from './test_utils';
+import {createModuleWithDeclarations, getText} from './test_utils';
 
 describe('find references', () => {
   let env: LanguageServiceTestEnvironment;
@@ -30,7 +30,7 @@ describe('find references', () => {
           }`);
     const appFile = {name: _('/app.ts'), contents: text};
     const templateFile = {name: _('/app.html'), contents: '{{myProp}}'};
-    createModuleWithDeclarations([appFile], [templateFile]);
+    env = createModuleWithDeclarations([appFile], [templateFile]);
     const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
     expect(refs.length).toBe(2);
     assertFileNames(refs, ['app.html', 'app.ts']);
@@ -46,7 +46,7 @@ describe('find references', () => {
             myP¦rop!: string;
           }`);
     const appFile = {name: _('/app.ts'), contents: text};
-    createModuleWithDeclarations([appFile]);
+    env = createModuleWithDeclarations([appFile]);
     const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
     expect(refs.length).toBe(2);
     assertFileNames(refs, ['app.ts']);
@@ -66,7 +66,7 @@ describe('find references', () => {
     };
     const {text, cursor} = extractCursorInfo('{{myP¦rop}}');
     const templateFile = {name: _('/app.html'), contents: text};
-    createModuleWithDeclarations([appFile], [templateFile]);
+    env = createModuleWithDeclarations([appFile], [templateFile]);
     const refs = getReferencesAtPosition(_('/app.html'), cursor)!;
     expect(refs.length).toBe(2);
     assertFileNames(refs, ['app.html', 'app.ts']);
@@ -82,7 +82,7 @@ describe('find references', () => {
             setTitle(s: number) {}
           }`);
     const appFile = {name: _('/app.ts'), contents: text};
-    createModuleWithDeclarations([appFile]);
+    env = createModuleWithDeclarations([appFile]);
     const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
     expect(refs.length).toBe(2);
 
@@ -100,7 +100,7 @@ describe('find references', () => {
             setTitle(s: string) {}
           }`);
     const appFile = {name: _('/app.ts'), contents: text};
-    createModuleWithDeclarations([appFile]);
+    env = createModuleWithDeclarations([appFile]);
     const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
     expect(refs.length).toBe(2);
 
@@ -121,7 +121,7 @@ describe('find references', () => {
     const templateFileWithCursor = `<div (click)="ti¦tle = 'newtitle'"></div>`;
     const {text, cursor} = extractCursorInfo(templateFileWithCursor);
     const templateFile = {name: _('/app.html'), contents: text};
-    createModuleWithDeclarations([appFile], [templateFile]);
+    env = createModuleWithDeclarations([appFile], [templateFile]);
     const refs = getReferencesAtPosition(_('/app.html'), cursor)!;
     expect(refs.length).toBe(2);
 
@@ -142,7 +142,7 @@ describe('find references', () => {
       name: _('/app.ts'),
       contents: text,
     };
-    createModuleWithDeclarations([appFile]);
+    env = createModuleWithDeclarations([appFile]);
     const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
     expect(refs.length).toBe(2);
 
@@ -162,7 +162,7 @@ describe('find references', () => {
       name: _('/app.ts'),
       contents: text,
     };
-    createModuleWithDeclarations([appFile]);
+    env = createModuleWithDeclarations([appFile]);
     const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
     // 3 references: the type definition, the value assignment, and the read in the template
     expect(refs.length).toBe(3);
@@ -191,7 +191,7 @@ describe('find references', () => {
     const templateFileWithCursor = `<div (click)="hero['name'] = bat¦man"></div>`;
     const {text, cursor} = extractCursorInfo(templateFileWithCursor);
     const templateFile = {name: _('/app.html'), contents: text};
-    createModuleWithDeclarations([appFile], [templateFile]);
+    env = createModuleWithDeclarations([appFile], [templateFile]);
     const refs = getReferencesAtPosition(_('/app.html'), cursor)!;
     expect(refs.length).toBe(2);
 
@@ -209,7 +209,7 @@ describe('find references', () => {
             title = '';
           }`);
       const appFile = {name: _('/app.ts'), contents: text};
-      createModuleWithDeclarations([appFile]);
+      env = createModuleWithDeclarations([appFile]);
       const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
       expect(refs.length).toBe(2);
       assertTextSpans(refs, ['myInput']);
@@ -236,7 +236,7 @@ describe('find references', () => {
       };
       const {text, cursor} = extractCursorInfo(templateWithCursor);
       const templateFile = {name: _('/app.html'), contents: text};
-      createModuleWithDeclarations([appFile], [templateFile]);
+      env = createModuleWithDeclarations([appFile], [templateFile]);
       const refs = getReferencesAtPosition(_('/app.html'), cursor)!;
       expect(refs.length).toBe(2);
       assertTextSpans(refs, ['myTemplate']);
@@ -274,7 +274,7 @@ describe('find references', () => {
         const templateWithCursor = '<div [dir] #dirRef="myDir"></div> {{ dirR¦ef }}';
         const {text, cursor} = extractCursorInfo(templateWithCursor);
         const templateFile = {name: _('/app.html'), contents: text};
-        createModuleWithDeclarations([appFile, dirFile], [templateFile]);
+        env = createModuleWithDeclarations([appFile, dirFile], [templateFile]);
         const refs = getReferencesAtPosition(_('/app.html'), cursor)!;
         expect(refs.length).toBe(2);
         assertFileNames(refs, ['app.html']);
@@ -285,7 +285,7 @@ describe('find references', () => {
         const fileWithCursor = '<div [dir] #dirRef="myDir"></div> {{ dirRef.dirV¦alue }}';
         const {text, cursor} = extractCursorInfo(fileWithCursor);
         const templateFile = {name: _('/app.html'), contents: text};
-        createModuleWithDeclarations([appFile, dirFile], [templateFile]);
+        env = createModuleWithDeclarations([appFile, dirFile], [templateFile]);
         const refs = getReferencesAtPosition(_('/app.html'), cursor)!;
         expect(refs.length).toBe(2);
         assertFileNames(refs, ['dir.ts', 'app.html']);
@@ -296,7 +296,7 @@ describe('find references', () => {
         const fileWithCursor = '<div [dir] #dirRef="myDir"></div> {{ dirRef?.dirV¦alue }}';
         const {text, cursor} = extractCursorInfo(fileWithCursor);
         const templateFile = {name: _('/app.html'), contents: text};
-        createModuleWithDeclarations([appFile, dirFile], [templateFile]);
+        env = createModuleWithDeclarations([appFile, dirFile], [templateFile]);
         const refs = getReferencesAtPosition(_('/app.html'), cursor)!;
         expect(refs.length).toBe(2);
         assertFileNames(refs, ['dir.ts', 'app.html']);
@@ -307,7 +307,7 @@ describe('find references', () => {
         const fileWithCursor = '<div [dir] #dirRef="myDir"></div> {{ dirRef?.doSometh¦ing() }}';
         const {text, cursor} = extractCursorInfo(fileWithCursor);
         const templateFile = {name: _('/app.html'), contents: text};
-        createModuleWithDeclarations([appFile, dirFile], [templateFile]);
+        env = createModuleWithDeclarations([appFile, dirFile], [templateFile]);
         const refs = getReferencesAtPosition(_('/app.html'), cursor)!;
         expect(refs.length).toBe(2);
         assertFileNames(refs, ['dir.ts', 'app.html']);
@@ -326,7 +326,7 @@ describe('find references', () => {
             heroes: string[] = [];
           }`);
       const appFile = {name: _('/app.ts'), contents: text};
-      createModuleWithDeclarations([appFile]);
+      env = createModuleWithDeclarations([appFile]);
       const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
       expect(refs.length).toBe(2);
       assertFileNames(refs, ['app.ts']);
@@ -347,7 +347,7 @@ describe('find references', () => {
             heroes: string[] = [];
           }`);
       const appFile = {name: _('/app.ts'), contents: text};
-      createModuleWithDeclarations([appFile]);
+      env = createModuleWithDeclarations([appFile]);
       const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
       expect(refs.length).toBe(2);
       assertFileNames(refs, ['app.ts']);
@@ -408,7 +408,7 @@ describe('find references', () => {
               heroes: Array<{name: string}> = [];
             }`);
       const appFile = {name: _('/app.ts'), contents: text};
-      createModuleWithDeclarations([appFile]);
+      env = createModuleWithDeclarations([appFile]);
       const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
       expect(refs.length).toBe(2);
       assertFileNames(refs, ['app.ts']);
@@ -444,7 +444,7 @@ describe('find references', () => {
       `;
       const {text, cursor} = extractCursorInfo(appContentsWithCursor);
       const appFile = {name: _('/app.ts'), contents: text};
-      createModuleWithDeclarations([appFile, prefixPipeFile]);
+      env = createModuleWithDeclarations([appFile, prefixPipeFile]);
       const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
       expect(refs.length).toBe(5);
       assertFileNames(refs, ['index.d.ts', 'prefix-pipe.ts', 'app.ts']);
@@ -463,7 +463,7 @@ describe('find references', () => {
       `;
       const {text, cursor} = extractCursorInfo(appContentsWithCursor);
       const appFile = {name: _('/app.ts'), contents: text};
-      createModuleWithDeclarations([appFile, prefixPipeFile]);
+      env = createModuleWithDeclarations([appFile, prefixPipeFile]);
       const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
       expect(refs.length).toBe(2);
       assertFileNames(refs, ['app.ts']);
@@ -490,7 +490,7 @@ describe('find references', () => {
           title = 'title';
         }`);
       const appFile = {name: _('/app.ts'), contents: text};
-      createModuleWithDeclarations([appFile, stringModelTestFile]);
+      env = createModuleWithDeclarations([appFile, stringModelTestFile]);
       const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
       expect(refs.length).toEqual(2);
       assertFileNames(refs, ['string-model.ts', 'app.ts']);
@@ -507,7 +507,7 @@ describe('find references', () => {
           title = 'title';
         }`);
       const appFile = {name: _('/app.ts'), contents: text};
-      createModuleWithDeclarations([appFile, stringModelTestFile]);
+      env = createModuleWithDeclarations([appFile, stringModelTestFile]);
       const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
       expect(refs.length).toEqual(2);
       assertFileNames(refs, ['string-model.ts', 'app.ts']);
@@ -534,7 +534,7 @@ describe('find references', () => {
           title = 'title';
         }`,
       };
-      createModuleWithDeclarations([appFile, stringModelTestFile]);
+      env = createModuleWithDeclarations([appFile, stringModelTestFile]);
       const refs = getReferencesAtPosition(_('/string-model.ts'), cursor)!;
       expect(refs.length).toEqual(2);
       assertFileNames(refs, ['app.ts', 'string-model.ts']);
@@ -576,7 +576,7 @@ describe('find references', () => {
           title = 'title';
         }`,
       };
-      createModuleWithDeclarations([appFile, stringModelTestFile, otherDirFile]);
+      env = createModuleWithDeclarations([appFile, stringModelTestFile, otherDirFile]);
       const refs = getReferencesAtPosition(_('/other-dir.ts'), cursor)!;
       expect(refs.length).toEqual(3);
       assertFileNames(refs, ['app.ts', 'string-model.ts', 'other-dir.ts']);
@@ -593,7 +593,7 @@ describe('find references', () => {
           title = 'title';
         }`);
       const appFile = {name: _('/app.ts'), contents: text};
-      createModuleWithDeclarations([appFile, stringModelTestFile]);
+      env = createModuleWithDeclarations([appFile, stringModelTestFile]);
       const refs = getReferencesAtPosition(_('/app.ts'), cursor)!;
       expect(refs.length).toEqual(2);
       assertFileNames(refs, ['string-model.ts', 'app.ts']);
@@ -703,39 +703,6 @@ describe('find references', () => {
           entry.originalContextSpan ? getText(fileContents, entry.originalContextSpan) : undefined,
     };
   }
-
-  function getFirstClassDeclaration(declaration: string) {
-    const matches = declaration.match(/(?:export class )(\w+)(?:\s|\{)/);
-    if (matches === null || matches.length !== 2) {
-      throw new Error(`Did not find exactly one exported class in: ${declaration}`);
-    }
-    return matches[1].trim();
-  }
-
-  function createModuleWithDeclarations(
-      filesWithClassDeclarations: TestFile[], externalResourceFiles: TestFile[] = []): void {
-    const externalClasses =
-        filesWithClassDeclarations.map(file => getFirstClassDeclaration(file.contents));
-    const externalImports = filesWithClassDeclarations.map(file => {
-      const className = getFirstClassDeclaration(file.contents);
-      const fileName = last(file.name.split('/')).replace('.ts', '');
-      return `import {${className}} from './${fileName}';`;
-    });
-    const contents = `
-        import {NgModule} from '@angular/core';
-        import {CommonModule} from '@angular/common';
-        ${externalImports.join('\n')}
-
-        @NgModule({
-          declarations: [${externalClasses.join(',')}],
-          imports: [CommonModule],
-        })
-        export class AppModule {}
-      `;
-    const moduleFile = {name: _('/app-module.ts'), contents, isRoot: true};
-    env = LanguageServiceTestEnvironment.setup(
-        [moduleFile, ...filesWithClassDeclarations, ...externalResourceFiles]);
-  }
 });
 
 function assertFileNames(refs: Array<{fileName: string}>, expectedFileNames: string[]) {
diff --git a/packages/language-service/ivy/test/test_utils.ts b/packages/language-service/ivy/test/test_utils.ts
index 9a96c2bad3..2d7253f91b 100644
--- a/packages/language-service/ivy/test/test_utils.ts
+++ b/packages/language-service/ivy/test/test_utils.ts
@@ -6,7 +6,48 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import {absoluteFrom as _} from '@angular/compiler-cli/src/ngtsc/file_system';
+import {TestFile} from '@angular/compiler-cli/src/ngtsc/file_system/testing';
+import {LanguageServiceTestEnvironment} from '@angular/language-service/ivy/test/env';
 
 export function getText(contents: string, textSpan: ts.TextSpan) {
   return contents.substr(textSpan.start, textSpan.length);
 }
+
+function last<T>(array: T[]): T {
+  return array[array.length - 1];
+}
+
+function getFirstClassDeclaration(declaration: string) {
+  const matches = declaration.match(/(?:export class )(\w+)(?:\s|\{)/);
+  if (matches === null || matches.length !== 2) {
+    throw new Error(`Did not find exactly one exported class in: ${declaration}`);
+  }
+  return matches[1].trim();
+}
+
+export function createModuleWithDeclarations(
+    filesWithClassDeclarations: TestFile[],
+    externalResourceFiles: TestFile[] = []): LanguageServiceTestEnvironment {
+  const externalClasses =
+      filesWithClassDeclarations.map(file => getFirstClassDeclaration(file.contents));
+  const externalImports = filesWithClassDeclarations.map(file => {
+    const className = getFirstClassDeclaration(file.contents);
+    const fileName = last(file.name.split('/')).replace('.ts', '');
+    return `import {${className}} from './${fileName}';`;
+  });
+  const contents = `
+        import {NgModule} from '@angular/core';
+        import {CommonModule} from '@angular/common';
+        ${externalImports.join('\n')}
+
+        @NgModule({
+          declarations: [${externalClasses.join(',')}],
+          imports: [CommonModule],
+        })
+        export class AppModule {}
+      `;
+  const moduleFile = {name: _('/app-module.ts'), contents, isRoot: true};
+  return LanguageServiceTestEnvironment.setup(
+      [moduleFile, ...filesWithClassDeclarations, ...externalResourceFiles]);
+}