Add unit-tests

__tests__/installer.test.ts

@@ -107,6 +107,15 @@ describe('DotnetCoreInstaller tests', () => {
     expect(process.env.PATH?.startsWith(toolDir)).toBe(true);
   }, 600000); //This needs some time to download on "slower" internet connections
 
+  it('Returns string with installed SDK version', async () => {
+    const version = '3.1.120';
+    let installedVersion: string;
+
+    installedVersion = await getDotnet(version);
+
+    expect(installedVersion).toBe('3.1.120');
+  }, 600000);
+
   it('Throws if no location contains correct dotnet version', async () => {
     await expect(async () => {
       await getDotnet('1000.0.0');
@@ -267,11 +276,15 @@ function normalizeFileContents(contents: string): string {
     .replace(new RegExp('\r', 'g'), '\n');
 }
 
-async function getDotnet(version: string, quality: string = ''): Promise<void> {
+async function getDotnet(
+  version: string,
+  quality: string = ''
+): Promise<string> {
   const dotnetInstaller = new installer.DotnetCoreInstaller(
     version,
     quality as QualityOptions
   );
-  await dotnetInstaller.installDotnet();
+  const installedVersion = await dotnetInstaller.installDotnet();
   installer.DotnetCoreInstaller.addToPath();
+  return installedVersion;
 }

__tests__/setup-dotnet.test.ts

@@ -1,4 +1,5 @@
 import * as io from '@actions/io';
+import * as core from '@actions/core';
 import fs from 'fs';
 import os from 'os';
 import path from 'path';
@@ -20,6 +21,8 @@ if (IS_WINDOWS) {
 const tempDir = path.join(__dirname, 'runner', 'temp2');
 
 describe('setup-dotnet tests', () => {
+  let getMultilineInputSpy = jest.spyOn(core, 'getMultilineInput');
+
   beforeAll(async () => {
     process.env.RUNNER_TOOL_CACHE = toolDir;
     process.env.DOTNET_INSTALL_DIR = toolDir;
@@ -59,4 +62,18 @@ describe('setup-dotnet tests', () => {
       expect(fs.existsSync(path.join(toolDir, 'dotnet'))).toBe(true);
     }
   }, 400000);
+
+  it('Sets output with the installed version', async () => {
+    const versions = ['3.1.201', '6.0.401'];
+
+    let setOutputSpy = jest.spyOn(core, 'getMultilineInput');
+
+    getMultilineInputSpy.mockImplementation(() => {
+      return versions;
+    });
+
+    await setup.run();
+
+    expect(setOutputSpy).toBeCalledWith('dotnet-version', '3.1.201');
+  }, 400000);
 });

src/installer.ts

@@ -164,7 +164,7 @@ export class DotnetCoreInstaller {
     }
   }
 
-  public async installDotnet() {
+  public async installDotnet(): Promise<string> {
     const windowsDefaultOptions = [
       '-NoLogo',
       '-Sta',