diff --git a/__tests__/authutil.test.ts b/__tests__/authutil.test.ts
index 594c6a13..458ceb12 100644
--- a/__tests__/authutil.test.ts
+++ b/__tests__/authutil.test.ts
@@ -123,6 +123,7 @@ describe('authutil tests', () => {
     expect(rc['registry']).toBe('https://registry.npmjs.org/');
     expect(rc['always-auth']).toBe('true');
   });
+
   it('It is already set the NODE_AUTH_TOKEN export it ', async () => {
     process.env.NODE_AUTH_TOKEN = 'foobar';
     await auth.configAuthentication('npm.pkg.github.com', 'false');
@@ -132,4 +133,84 @@ describe('authutil tests', () => {
     expect(rc['always-auth']).toBe('false');
     expect(process.env.NODE_AUTH_TOKEN).toEqual('foobar');
   });
+
+  it('configAuthentication should overwrite non-scoped with non-scoped', async () => {
+    fs.writeFileSync(rcFile, 'registry=NNN');
+    await auth.configAuthentication('https://registry.npmjs.org/', 'true');
+    let contents = fs.readFileSync(rcFile, {encoding: 'utf8'});
+    expect(contents).toBe(
+      `//registry.npmjs.org/:_authToken=\${NODE_AUTH_TOKEN}${os.EOL}registry=https://registry.npmjs.org/${os.EOL}always-auth=true`
+    );
+  });
+
+  it('configAuthentication should overwrite only non-scoped', async () => {
+    fs.writeFileSync(rcFile, `registry=NNN${os.EOL}@myscope:registry=MMM`);
+    await auth.configAuthentication('https://registry.npmjs.org/', 'true');
+    let contents = fs.readFileSync(rcFile, {encoding: 'utf8'});
+    expect(contents).toBe(
+      `@myscope:registry=MMM${os.EOL}//registry.npmjs.org/:_authToken=\${NODE_AUTH_TOKEN}${os.EOL}registry=https://registry.npmjs.org/${os.EOL}always-auth=true`
+    );
+  });
+
+  it('configAuthentication should add non-scoped to scoped', async () => {
+    fs.writeFileSync(rcFile, '@myscope:registry=NNN');
+    await auth.configAuthentication('https://registry.npmjs.org/', 'true');
+    let contents = fs.readFileSync(rcFile, {encoding: 'utf8'});
+    expect(contents).toBe(
+      `@myscope:registry=NNN${os.EOL}//registry.npmjs.org/:_authToken=\${NODE_AUTH_TOKEN}${os.EOL}registry=https://registry.npmjs.org/${os.EOL}always-auth=true`
+    );
+  });
+
+  it('configAuthentication should overwrite scoped with scoped', async () => {
+    process.env['INPUT_SCOPE'] = 'myscope';
+    fs.writeFileSync(rcFile, `@myscope:registry=NNN`);
+    await auth.configAuthentication('https://registry.npmjs.org/', 'true');
+    let contents = fs.readFileSync(rcFile, {encoding: 'utf8'});
+    expect(contents).toBe(
+      `//registry.npmjs.org/:_authToken=\${NODE_AUTH_TOKEN}${os.EOL}@myscope:registry=https://registry.npmjs.org/${os.EOL}always-auth=true`
+    );
+  });
+
+  it('configAuthentication should overwrite only scoped', async () => {
+    process.env['INPUT_SCOPE'] = 'myscope';
+    fs.writeFileSync(rcFile, `registry=NNN${os.EOL}@myscope:registry=MMM`);
+    await auth.configAuthentication('https://registry.npmjs.org/', 'true');
+    let contents = fs.readFileSync(rcFile, {encoding: 'utf8'});
+    expect(contents).toBe(
+      `registry=NNN${os.EOL}//registry.npmjs.org/:_authToken=\${NODE_AUTH_TOKEN}${os.EOL}@myscope:registry=https://registry.npmjs.org/${os.EOL}always-auth=true`
+    );
+  });
+
+  it('configAuthentication should add scoped to non-scoped', async () => {
+    process.env['INPUT_SCOPE'] = 'myscope';
+    fs.writeFileSync(rcFile, `registry=MMM`);
+    await auth.configAuthentication('https://registry.npmjs.org/', 'true');
+    let contents = fs.readFileSync(rcFile, {encoding: 'utf8'});
+    expect(contents).toBe(
+      `registry=MMM${os.EOL}//registry.npmjs.org/:_authToken=\${NODE_AUTH_TOKEN}${os.EOL}@myscope:registry=https://registry.npmjs.org/${os.EOL}always-auth=true`
+    );
+  });
+
+  it('configAuthentication should overwrite only one scoped', async () => {
+    process.env['INPUT_SCOPE'] = 'myscope';
+    fs.writeFileSync(
+      rcFile,
+      `@otherscope:registry=NNN${os.EOL}@myscope:registry=MMM`
+    );
+    await auth.configAuthentication('https://registry.npmjs.org/', 'true');
+    let contents = fs.readFileSync(rcFile, {encoding: 'utf8'});
+    expect(contents).toBe(
+      `@otherscope:registry=NNN${os.EOL}//registry.npmjs.org/:_authToken=\${NODE_AUTH_TOKEN}${os.EOL}@myscope:registry=https://registry.npmjs.org/${os.EOL}always-auth=true`
+    );
+  });
+
+  it('configAuthentication should add scoped to another scoped', async () => {
+    process.env['INPUT_SCOPE'] = 'myscope';
+    fs.writeFileSync(rcFile, `@otherscope:registry=MMM`);
+    await auth.configAuthentication('https://registry.npmjs.org/', 'true');
+    let contents = fs.readFileSync(rcFile, {encoding: 'utf8'});
+    expect(contents).toBe(
+      `@otherscope:registry=MMM${os.EOL}//registry.npmjs.org/:_authToken=\${NODE_AUTH_TOKEN}${os.EOL}@myscope:registry=https://registry.npmjs.org/${os.EOL}always-auth=true`
+    );
+  });
 });