add unit tests

__tests__/installer.test.ts

@@ -909,4 +909,44 @@ describe('setup-node', () => {
       );
     });
   });
+
+  describe('latest alias syntax', () => {
+    it.each(['latest', 'current', 'node'])('download the %s version if alias is provided', async (inputVersion) => {
+      // Arrange
+      inputs['node-version'] = inputVersion;
+
+      os.platform = 'darwin';
+      os.arch = 'x64';
+
+      const expectedVersion = nodeTestDist[0];
+
+      let expectedUrl = `https://nodejs.org/dist/${expectedVersion.version}/node-${expectedVersion.version}-${os.platform}-${os.arch}.tar.gz`;
+
+      findSpy.mockImplementation(() => '');
+      getManifestSpy.mockImplementation(() => {
+        throw new Error('Unable to download manifest');
+      });
+
+      // Act
+      await main.run();
+
+      // Assert
+      expect(logSpy).toHaveBeenCalledWith(
+        `Attempting to download ${inputVersion}...`
+      );
+
+      expect(logSpy).toHaveBeenCalledWith(
+        'Unable to download manifest'
+      );
+
+      expect(logSpy).toHaveBeenCalledWith(
+        'getting latest node version...'
+      );
+
+      expect(logSpy).toHaveBeenCalledWith(
+        `Acquiring ${expectedVersion.version.substring(1, expectedVersion.version.length)} - ${os.arch} from ${expectedUrl}`
+      );
+
+    });
+  });
 });