Refactor and update unit-tests (#418)

* Update unit-tests and dotnet-install scripts

__tests__/installation-scripts.test.ts

@@ -0,0 +1,52 @@
+import path from 'path';
+import fs from 'fs';
+import * as hc from '@actions/http-client';
+
+describe('Dotnet installation scripts tests', () => {
+  it('Uses an up to date bash download script', async () => {
+    const httpCallbackClient = new hc.HttpClient('setup-dotnet-test', [], {
+      allowRetries: true,
+      maxRetries: 3
+    });
+    const response: hc.HttpClientResponse = await httpCallbackClient.get(
+      'https://dot.net/v1/dotnet-install.sh'
+    );
+    expect(response.message.statusCode).toBe(200);
+    const upToDateContents: string = await response.readBody();
+    const currentContents: string = fs
+      .readFileSync(
+        path.join(__dirname, '..', 'externals', 'install-dotnet.sh')
+      )
+      .toString();
+    expect(normalizeFileContents(currentContents)).toBe(
+      normalizeFileContents(upToDateContents)
+    );
+  }, 30000);
+
+  it('Uses an up to date powershell download script', async () => {
+    const httpCallbackClient = new hc.HttpClient('setup-dotnet-test', [], {
+      allowRetries: true,
+      maxRetries: 3
+    });
+    const response: hc.HttpClientResponse = await httpCallbackClient.get(
+      'https://dot.net/v1/dotnet-install.ps1'
+    );
+    expect(response.message.statusCode).toBe(200);
+    const upToDateContents: string = await response.readBody();
+    const currentContents: string = fs
+      .readFileSync(
+        path.join(__dirname, '..', 'externals', 'install-dotnet.ps1')
+      )
+      .toString();
+    expect(normalizeFileContents(currentContents)).toBe(
+      normalizeFileContents(upToDateContents)
+    );
+  }, 30000);
+});
+
+function normalizeFileContents(contents: string): string {
+  return contents
+    .trim()
+    .replace(new RegExp('\r\n', 'g'), '\n')
+    .replace(new RegExp('\r', 'g'), '\n');
+}