test(ivy): ngcc refactor mock file-systems to make each spec independent (#30591)

Previously each test relied on large shared mock file-systems, which
makes it difficult to reason about what is actually being tested.

This commit breaks up these big mock file-systems into smaller more
focused chunks.

PR Close #30591

packages/compiler-cli/ngcc/test/packages/entry_point_spec.ts

@@ -19,7 +19,6 @@ runInEachFileSystem(() => {
     let fs: FileSystem;
 
     beforeEach(() => {
-      setupMockFileSystem();
       SOME_PACKAGE = absoluteFrom('/some_package');
       _ = absoluteFrom;
       fs = getFileSystem();
@@ -27,6 +26,16 @@ runInEachFileSystem(() => {
 
     it('should return an object containing absolute paths to the formats of the specified entry-point',
        () => {
+         loadTestFiles([
+           {
+             name: _('/some_package/valid_entry_point/package.json'),
+             contents: createPackageJson('valid_entry_point')
+           },
+           {
+             name: _('/some_package/valid_entry_point/valid_entry_point.metadata.json'),
+             contents: 'some meta data'
+           },
+         ]);
          const entryPoint = getEntryPointInfo(
              fs, new MockLogger(), SOME_PACKAGE, _('/some_package/valid_entry_point'));
          expect(entryPoint).toEqual({
@@ -40,12 +49,28 @@ runInEachFileSystem(() => {
        });
 
     it('should return null if there is no package.json at the entry-point path', () => {
+      loadTestFiles([
+        {
+          name: _('/some_package/missing_package_json/missing_package_json.metadata.json'),
+          contents: 'some meta data'
+        },
+      ]);
       const entryPoint = getEntryPointInfo(
           fs, new MockLogger(), SOME_PACKAGE, _('/some_package/missing_package_json'));
       expect(entryPoint).toBe(null);
     });
 
     it('should return null if there is no typings or types field in the package.json', () => {
+      loadTestFiles([
+        {
+          name: _('/some_package/missing_typings/package.json'),
+          contents: createPackageJson('missing_typings', {excludes: ['typings']})
+        },
+        {
+          name: _('/some_package/missing_typings/missing_typings.metadata.json'),
+          contents: 'some meta data'
+        },
+      ]);
       const entryPoint =
           getEntryPointInfo(fs, new MockLogger(), SOME_PACKAGE, _('/some_package/missing_typings'));
       expect(entryPoint).toBe(null);
@@ -53,6 +78,12 @@ runInEachFileSystem(() => {
 
     it('should return an object with `compiledByAngular` set to false if there is no metadata.json file next to the typing file',
        () => {
+         loadTestFiles([
+           {
+             name: _('/some_package/missing_metadata/package.json'),
+             contents: createPackageJson('missing_metadata')
+           },
+         ]);
          const entryPoint = getEntryPointInfo(
              fs, new MockLogger(), SOME_PACKAGE, _('/some_package/missing_metadata'));
          expect(entryPoint).toEqual({
@@ -66,6 +97,17 @@ runInEachFileSystem(() => {
        });
 
     it('should work if the typings field is named `types', () => {
+      loadTestFiles([
+        {
+          name: _('/some_package/types_rather_than_typings/package.json'),
+          contents: createPackageJson('types_rather_than_typings', {}, 'types')
+        },
+        {
+          name:
+              _('/some_package/types_rather_than_typings/types_rather_than_typings.metadata.json'),
+          contents: 'some meta data'
+        },
+      ]);
       const entryPoint = getEntryPointInfo(
           fs, new MockLogger(), SOME_PACKAGE, _('/some_package/types_rather_than_typings'));
       expect(entryPoint).toEqual({
@@ -79,70 +121,7 @@ runInEachFileSystem(() => {
     });
 
     it('should work with Angular Material style package.json', () => {
-      const entryPoint =
-          getEntryPointInfo(fs, new MockLogger(), SOME_PACKAGE, _('/some_package/material_style'));
-      expect(entryPoint).toEqual({
-        name: 'some_package/material_style',
-        package: SOME_PACKAGE,
-        path: _('/some_package/material_style'),
-        typings: _(`/some_package/material_style/material_style.d.ts`),
-        packageJson: loadPackageJson(fs, '/some_package/material_style'),
-        compiledByAngular: true,
-      });
-    });
-
-    it('should return null if the package.json is not valid JSON', () => {
-      const entryPoint = getEntryPointInfo(
-          fs, new MockLogger(), SOME_PACKAGE, _('/some_package/unexpected_symbols'));
-      expect(entryPoint).toBe(null);
-    });
-  });
-
-  function setupMockFileSystem(): void {
-    const _ = absoluteFrom;
       loadTestFiles([
-      {
-        name: _('/some_package/valid_entry_point/package.json'),
-        contents: createPackageJson('valid_entry_point')
-      },
-      {
-        name: _('/some_package/valid_entry_point/valid_entry_point.metadata.json'),
-        contents: 'some meta data'
-      },
-      // no package.json!
-      {
-        name: _('/some_package/missing_package_json/missing_package_json.metadata.json'),
-        contents: 'some meta data'
-      },
-      {
-        name: _('/some_package/missing_typings/package.json'),
-        contents: createPackageJson('missing_typings', {excludes: ['typings']})
-      },
-      {
-        name: _('/some_package/missing_typings/missing_typings.metadata.json'),
-        contents: 'some meta data'
-      },
-      {
-        name: _('/some_package/types_rather_than_typings/package.json'),
-        contents: createPackageJson('types_rather_than_typings', {}, 'types')
-      },
-      {
-        name: _('/some_package/types_rather_than_typings/types_rather_than_typings.metadata.json'),
-        contents: 'some meta data'
-      },
-      {
-        name: _('/some_package/missing_esm2015/package.json'),
-        contents: createPackageJson('missing_fesm2015', {excludes: ['esm2015', 'fesm2015']})
-      },
-      {
-        name: _('/some_package/missing_esm2015/missing_esm2015.metadata.json'),
-        contents: 'some meta data'
-      },
-      // no metadata.json!
-      {
-        name: _('/some_package/missing_metadata/package.json'),
-        contents: createPackageJson('missing_metadata')
-      },
         {
           name: _('/some_package/material_style/package.json'),
           contents: `{
@@ -157,6 +136,21 @@ runInEachFileSystem(() => {
           name: _('/some_package/material_style/material_style.metadata.json'),
           contents: 'some meta data'
         },
+      ]);
+      const entryPoint =
+          getEntryPointInfo(fs, new MockLogger(), SOME_PACKAGE, _('/some_package/material_style'));
+      expect(entryPoint).toEqual({
+        name: 'some_package/material_style',
+        package: SOME_PACKAGE,
+        path: _('/some_package/material_style'),
+        typings: _(`/some_package/material_style/material_style.d.ts`),
+        packageJson: loadPackageJson(fs, '/some_package/material_style'),
+        compiledByAngular: true,
+      });
+    });
+
+    it('should return null if the package.json is not valid JSON', () => {
+      loadTestFiles([
         // package.json might not be a valid JSON
         // for example, @schematics/angular contains a package.json blueprint
         // with unexpected symbols
@@ -165,7 +159,11 @@ runInEachFileSystem(() => {
           contents: '{"devDependencies": {<% if (!minimal) { %>"@types/jasmine": "~2.8.8" <% } %>}}'
         },
       ]);
-  }
+      const entryPoint = getEntryPointInfo(
+          fs, new MockLogger(), SOME_PACKAGE, _('/some_package/unexpected_symbols'));
+      expect(entryPoint).toBe(null);
+    });
+  });
 
   function createPackageJson(
       packageName: string, {excludes}: {excludes?: string[]} = {},