diff --git a/test/fixtures/build-withConfig/src/index.ts b/test/fixtures/build-withConfig/src/index.ts
index 90a62171f..b93cbd2ec 100644
--- a/test/fixtures/build-withConfig/src/index.ts
+++ b/test/fixtures/build-withConfig/src/index.ts
@@ -6,4 +6,4 @@ export const sum = (a: number, b: number) => {
 
 const bar = split('bar');
 
-console.log(`${split('bar').join('')} ${sum(bar.length, -3)}`);
+export const signature = `${split('bar').join('')} ${sum(bar.length, -3)}`;
diff --git a/test/fixtures/build-withConfig/tsdx.config.closure-advanced.js b/test/fixtures/build-withConfig/tsdx.config.closure-advanced.js
index 59c86e9f3..1decbc3ab 100644
--- a/test/fixtures/build-withConfig/tsdx.config.closure-advanced.js
+++ b/test/fixtures/build-withConfig/tsdx.config.closure-advanced.js
@@ -1,11 +1,4 @@
-const fs = require('fs-extra');
-
 module.exports = {
-  rollup(config, options) {
-    const plugins = config.plugins.map(plugin => plugin.name);
-    fs.writeJSON('./plugins.json', plugins);
-    return config;
-  },
   closureCompilerOptions: {
     compilation_level: 'ADVANCED_OPTIMIZATIONS',
   },
diff --git a/test/fixtures/build-withConfig/tsdx.config.closure-simple.js b/test/fixtures/build-withConfig/tsdx.config.closure-simple.js
index 70b8801be..8d88cf212 100644
--- a/test/fixtures/build-withConfig/tsdx.config.closure-simple.js
+++ b/test/fixtures/build-withConfig/tsdx.config.closure-simple.js
@@ -1,7 +1,6 @@
 module.exports = {
-  /* SIMPLE_OPTIMIZATIONS by default
   closureCompilerOptions: {
-    compilation_level: 'SIMPLE_OPTIMIZATIONS',
+    //SIMPLE_OPTIMIZATIONS level is default option
+    //compilation_level: 'SIMPLE_OPTIMIZATIONS',
   },
-  */
 };
diff --git a/test/tests/tsdx-build-closure-compiler.test.js b/test/tests/tsdx-build-closure-compiler.test.js
index f81fda9e6..c9ef19c1c 100644
--- a/test/tests/tsdx-build-closure-compiler.test.js
+++ b/test/tests/tsdx-build-closure-compiler.test.js
@@ -14,7 +14,7 @@ describe('tsdx build with closure compiler', () => {
     util.teardownStage(stageName);
   });
 
-  it('should compile files with default options', () => {
+  it('should minify bundle with default options', () => {
     util.setupStageWithFixture(stageName, 'build-withConfig');
     shell.mv('-f', 'tsdx.config.closure-simple.js', 'tsdx.config.js');
 
@@ -36,12 +36,14 @@ describe('tsdx build with closure compiler', () => {
 
     expect(shell.test('-f', 'dist/index.d.ts')).toBeTruthy();
 
-    output = shell.exec('node dist/index.js');
-    expect(output.code).toBe(0);
+    // only closure compiler minifies bundle to `signature="bar 0"`
+    output = shell.grep('bar 0', [
+      'dist/build-withconfig.esm.production.min.js',
+    ]);
     expect(/bar 0/.test(output.stdout)).toBeTruthy();
   });
 
-  it('should compile files with advanced options', () => {
+  it('should minify bundle with advanced options', () => {
     util.setupStageWithFixture(stageName, 'build-withConfig');
     shell.mv('-f', 'tsdx.config.closure-advanced.js', 'tsdx.config.js');
 
@@ -50,11 +52,6 @@ describe('tsdx build with closure compiler', () => {
     );
     expect(output.code).toBe(0);
 
-    // ensure we use closure-compiler instead of terser
-    const plugins = require(`../../${stageName}/plugins.json`);
-    expect(plugins.includes('closure-compiler')).toBeTruthy();
-    expect(plugins.includes('terser')).toBeFalsy();
-
     expect(shell.test('-f', 'dist/index.js')).toBeTruthy();
     expect(
       shell.test('-f', 'dist/build-withconfig.cjs.development.js')
@@ -68,8 +65,10 @@ describe('tsdx build with closure compiler', () => {
 
     expect(shell.test('-f', 'dist/index.d.ts')).toBeTruthy();
 
-    output = shell.exec('node dist/index.js');
-    expect(output.code).toBe(0);
+    // only closure compiler minifies bundle to `signature="bar 0"`
+    output = shell.grep('bar 0', [
+      'dist/build-withconfig.esm.production.min.js',
+    ]);
     expect(/bar 0/.test(output.stdout)).toBeTruthy();
   });