test: add git prerequisite validation with loud failure messages

Add test-prerequisites.spec.ts that validates git availability and fails
loudly with clear, actionable instructions when prerequisites are missing.

This ensures tests crash immediately with helpful error messages instead of
failing cryptically later. Emphasizes that angular-cli-ghpages is built on
top of git and requires:
- git executable on PATH
- running in a git repository
- origin remote configured

Each test failure includes installation/fix commands for macOS, Linux, and
Windows.

Test count: 374 → 377 tests

Author: JohannesHoppe

src/test-prerequisites.spec.ts

@@ -0,0 +1,160 @@
+import { execSync } from 'child_process';
+
+/**
+ * TEST PREREQUISITES VALIDATION
+ *
+ * This test suite validates that the required development environment
+ * is correctly set up. These tests intentionally FAIL LOUDLY with clear
+ * instructions rather than skipping silently.
+ *
+ * angular-cli-ghpages is built on top of git. Without git, nothing works.
+ */
+
+describe('Test Prerequisites', () => {
+  describe('Git availability', () => {
+    let gitVersion: string;
+
+    it('must have git executable available on PATH', () => {
+      try {
+        gitVersion = execSync('git --version', { encoding: 'utf8', stdio: 'pipe' }).trim();
+      } catch (error) {
+        throw new Error(
+          '\n\n' +
+            '====================================================================\n' +
+            '  PREREQUISITE FAILURE: Git is not installed or not on PATH\n' +
+            '====================================================================\n' +
+            '\n' +
+            'angular-cli-ghpages is built on top of git.\n' +
+            'Tests cannot run without git being available.\n' +
+            '\n' +
+            'To fix this:\n' +
+            '\n' +
+            '  macOS:\n' +
+            '    brew install git\n' +
+            '    # or install Xcode Command Line Tools:\n' +
+            '    xcode-select --install\n' +
+            '\n' +
+            '  Ubuntu/Debian:\n' +
+            '    sudo apt-get update\n' +
+            '    sudo apt-get install git\n' +
+            '\n' +
+            '  Windows:\n' +
+            '    Download from https://git-scm.com/download/win\n' +
+            '    # or use winget:\n' +
+            '    winget install Git.Git\n' +
+            '\n' +
+            '  Verify installation:\n' +
+            '    git --version\n' +
+            '\n' +
+            '====================================================================\n'
+        );
+      }
+
+      // If we got here, git is available
+      expect(gitVersion).toMatch(/^git version/);
+    });
+
+    it('must be running in a git repository', () => {
+      // Only run if git is available (previous test passed)
+      let gitDir: string;
+
+      try {
+        gitDir = execSync('git rev-parse --git-dir', {
+          encoding: 'utf8',
+          stdio: 'pipe',
+          cwd: '/Users/johanneshoppe/Work/angular-schule/angular-cli-ghpages'
+        }).trim();
+      } catch (error) {
+        throw new Error(
+          '\n\n' +
+            '====================================================================\n' +
+            '  PREREQUISITE FAILURE: Not running in a git repository\n' +
+            '====================================================================\n' +
+            '\n' +
+            'angular-cli-ghpages tests must run within a git repository.\n' +
+            '\n' +
+            'Current directory:\n' +
+            '  /Users/johanneshoppe/Work/angular-schule/angular-cli-ghpages\n' +
+            '\n' +
+            'To fix this:\n' +
+            '\n' +
+            '  If you cloned this repository:\n' +
+            '    # Ensure you are in the correct directory\n' +
+            '    cd /Users/johanneshoppe/Work/angular-schule/angular-cli-ghpages\n' +
+            '    git status\n' +
+            '\n' +
+            '  If you downloaded as ZIP:\n' +
+            '    # Clone the repository instead:\n' +
+            '    git clone https://github.com/angular-schule/angular-cli-ghpages.git\n' +
+            '    cd angular-cli-ghpages\n' +
+            '\n' +
+            '  If git was initialized but corrupted:\n' +
+            '    # Check if .git directory exists:\n' +
+            '    ls -la .git\n' +
+            '    # If corrupted, re-clone the repository\n' +
+            '\n' +
+            '====================================================================\n'
+        );
+      }
+
+      // If we got here, we are in a git repository
+      expect(gitDir).toBeDefined();
+      expect(gitDir.length).toBeGreaterThan(0);
+    });
+
+    it('must have origin remote configured', () => {
+      // Only run if git is available and we are in a repo (previous tests passed)
+      let remoteUrl: string;
+
+      try {
+        remoteUrl = execSync('git config --get remote.origin.url', {
+          encoding: 'utf8',
+          stdio: 'pipe',
+          cwd: '/Users/johanneshoppe/Work/angular-schule/angular-cli-ghpages'
+        }).trim();
+      } catch (error) {
+        throw new Error(
+          '\n\n' +
+            '====================================================================\n' +
+            '  PREREQUISITE FAILURE: No origin remote configured\n' +
+            '====================================================================\n' +
+            '\n' +
+            'angular-cli-ghpages tests expect a git origin remote to be configured.\n' +
+            '\n' +
+            'To fix this:\n' +
+            '\n' +
+            '  Add the origin remote:\n' +
+            '    git remote add origin https://github.com/angular-schule/angular-cli-ghpages.git\n' +
+            '\n' +
+            '  Verify it was added:\n' +
+            '    git remote -v\n' +
+            '\n' +
+            '  If origin exists but is misconfigured:\n' +
+            '    # View current remotes:\n' +
+            '    git remote -v\n' +
+            '\n' +
+            '    # Update origin URL:\n' +
+            '    git remote set-url origin https://github.com/angular-schule/angular-cli-ghpages.git\n' +
+            '\n' +
+            '  Expected origin:\n' +
+            '    https://github.com/angular-schule/angular-cli-ghpages.git\n' +
+            '    or\n' +
+            '    git@github.com:angular-schule/angular-cli-ghpages.git\n' +
+            '\n' +
+            '====================================================================\n'
+        );
+      }
+
+      // If we got here, origin is configured
+      expect(remoteUrl).toBeDefined();
+      expect(remoteUrl.length).toBeGreaterThan(0);
+      // Verify it looks like a valid git URL (either HTTPS or SSH)
+      expect(
+        remoteUrl.includes('github.com') ||
+          remoteUrl.includes('http') ||
+          remoteUrl.includes('git@')
+      ).toBe(true);
+    });
+  });
+
+});