diff --git a/__tests__/context.test.ts b/__tests__/context.test.ts
index a77f44b..886619b 100644
--- a/__tests__/context.test.ts
+++ b/__tests__/context.test.ts
@@ -2,13 +2,21 @@ import osm = require('os');
 
 import {getInputs} from '../src/context';
 
+test('without username getInputs throws errors', async () => {
+  expect(() => {
+    getInputs();
+  }).toThrowError('Input required and not supplied: username');
+});
+
 test('without password getInputs throws errors', async () => {
+  process.env['INPUT_USERNAME'] = 'dbowie';
   expect(() => {
     getInputs();
   }).toThrowError('Input required and not supplied: password');
 });
 
-test('with password getInputs does not error', async () => {
+test('with password and username getInputs does not error', async () => {
+  process.env['INPUT_USERNAME'] = 'dbowie';
   process.env['INPUT_PASSWORD'] = 'groundcontrol';
   expect(() => {
     getInputs();
diff --git a/__tests__/main.test.ts b/__tests__/main.test.ts
index 44c8f4e..062c7c2 100644
--- a/__tests__/main.test.ts
+++ b/__tests__/main.test.ts
@@ -17,7 +17,7 @@ test('errors when not run on linux platform', async () => {
   expect(coreSpy).toHaveBeenCalledWith('Only supported on linux platform');
 });
 
-test('errors without password', async () => {
+test('errors without username', async () => {
   const platSpy = jest.spyOn(osm, 'platform');
   platSpy.mockImplementation(() => 'linux');
 
@@ -25,26 +25,43 @@ test('errors without password', async () => {
 
   await run();
 
+  expect(coreSpy).toHaveBeenCalledWith('Input required and not supplied: username');
+});
+
+test('errors without password', async () => {
+  const platSpy = jest.spyOn(osm, 'platform');
+  platSpy.mockImplementation(() => 'linux');
+
+  const coreSpy: jest.SpyInstance = jest.spyOn(core, 'setFailed');
+
+  const username: string = 'dbowie';
+  process.env[`INPUT_USERNAME`] = username;
+
+  await run();
+
   expect(coreSpy).toHaveBeenCalledWith('Input required and not supplied: password');
 });
 
-test('successful with only password', async () => {
-    const platSpy = jest.spyOn(osm, 'platform');
-    platSpy.mockImplementation(() => 'linux');
-  
-    const setRegistrySpy: jest.SpyInstance = jest.spyOn(stateHelper, 'setRegistry');
-    const setLogoutSpy: jest.SpyInstance = jest.spyOn(stateHelper, 'setLogout');
-    const dockerSpy: jest.SpyInstance = jest.spyOn(docker, 'login');
-    dockerSpy.mockImplementation(() => {});
-  
-    const password: string = 'groundcontrol';
-    process.env[`INPUT_PASSWORD`] = password;
+test('successful with username and password', async () => {
+  const platSpy = jest.spyOn(osm, 'platform');
+  platSpy.mockImplementation(() => 'linux');
 
-    await run();
+  const setRegistrySpy: jest.SpyInstance = jest.spyOn(stateHelper, 'setRegistry');
+  const setLogoutSpy: jest.SpyInstance = jest.spyOn(stateHelper, 'setLogout');
+  const dockerSpy: jest.SpyInstance = jest.spyOn(docker, 'login');
+  dockerSpy.mockImplementation(() => {});
 
-    expect(setRegistrySpy).toHaveBeenCalledWith('');
-    expect(setLogoutSpy).toHaveBeenCalledWith('');
-    expect(dockerSpy).toHaveBeenCalledWith('', '', password);
+  const username: string = 'dbowie';
+  process.env[`INPUT_USERNAME`] = username;
+
+  const password: string = 'groundcontrol';
+  process.env[`INPUT_PASSWORD`] = password;
+
+  await run();
+
+  expect(setRegistrySpy).toHaveBeenCalledWith('');
+  expect(setLogoutSpy).toHaveBeenCalledWith('');
+  expect(dockerSpy).toHaveBeenCalledWith('', username, password);
 });
 
 test('calls docker login', async () => {
@@ -66,7 +83,7 @@ test('calls docker login', async () => {
   process.env[`INPUT_REGISTRY`] = registry;
 
   const logout: string = 'true';
-  process.env['INPUT_LOGOUT'] = logout
+  process.env['INPUT_LOGOUT'] = logout;
 
   await run();
 
diff --git a/action.yml b/action.yml
index 07c82e8..3766856 100644
--- a/action.yml
+++ b/action.yml
@@ -12,7 +12,7 @@ inputs:
     required: false
   username:
     description: 'Username used to log against the Docker registry'
-    required: false
+    required: true
   password:
     description: 'Password or personal access token used to log against the Docker registry'
     required: true
diff --git a/dist/index.js b/dist/index.js
index 712a13e..aec5702 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -496,6 +496,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 Object.defineProperty(exports, "__esModule", { value: true });
+exports.run = void 0;
 const os = __importStar(__webpack_require__(87));
 const core = __importStar(__webpack_require__(186));
 const context_1 = __webpack_require__(842);
@@ -505,19 +506,19 @@ function run() {
     return __awaiter(this, void 0, void 0, function* () {
         try {
             if (os.platform() !== 'linux') {
-                core.setFailed('Only supported on linux platform');
-                return;
+                throw new Error('Only supported on linux platform');
             }
-            let inputs = yield context_1.getInputs();
-            stateHelper.setRegistry(inputs.registry);
-            stateHelper.setLogout(inputs.logout);
-            yield docker.login(inputs.registry, inputs.username, inputs.password);
+            const { registry, username, password, logout } = context_1.getInputs();
+            stateHelper.setRegistry(registry);
+            stateHelper.setLogout(logout);
+            yield docker.login(registry, username, password);
         }
         catch (error) {
             core.setFailed(error.message);
         }
     });
 }
+exports.run = run;
 function logout() {
     return __awaiter(this, void 0, void 0, function* () {
         if (!stateHelper.logout) {
@@ -3640,27 +3641,16 @@ var __importStar = (this && this.__importStar) || function (mod) {
     __setModuleDefault(result, mod);
     return result;
 };
-var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
-    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
-    return new (P || (P = Promise))(function (resolve, reject) {
-        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
-        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
-        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
-        step((generator = generator.apply(thisArg, _arguments || [])).next());
-    });
-};
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.getInputs = void 0;
 const core = __importStar(__webpack_require__(186));
 function getInputs() {
-    return __awaiter(this, void 0, void 0, function* () {
-        return {
-            registry: core.getInput('registry'),
-            username: core.getInput('username'),
-            password: core.getInput('password', { required: true }),
-            logout: core.getInput('logout')
-        };
-    });
+    return {
+        registry: core.getInput('registry'),
+        username: core.getInput('username', { required: true }),
+        password: core.getInput('password', { required: true }),
+        logout: core.getInput('logout')
+    };
 }
 exports.getInputs = getInputs;
 //# sourceMappingURL=context.js.map
diff --git a/src/context.ts b/src/context.ts
index 3d24754..953ea21 100644
--- a/src/context.ts
+++ b/src/context.ts
@@ -10,7 +10,7 @@ export interface Inputs {
 export function getInputs(): Inputs {
   return {
     registry: core.getInput('registry'),
-    username: core.getInput('username'),
+    username: core.getInput('username', {required: true}),
     password: core.getInput('password', {required: true}),
     logout: core.getInput('logout')
   };