- introduce tests covering the action process itself

__tests__/main.test.ts

@@ -0,0 +1,34 @@
+import * as path from 'path';
+import * as process from 'process'
+import * as cp from 'child_process'
+
+test('missing values should result in failure', () => {
+  process.env['GITHUB_WORKSPACE'] = '.'
+  process.env['INPUT_CONFIGURATION'] = 'configuration.json'
+  const ip = path.join(__dirname, '..', 'lib', 'main.js')
+  const options: cp.ExecSyncOptions = {
+    env: process.env
+  }
+  try {
+    cp.execSync(`node ${ip}`, options).toString()
+    fail("Should not succeed, because values miss")
+  } catch (error) {
+    console.log(`correctly failed due to: ${error}`)
+  }
+})
+
+test('missing values should result in failure', () => {
+  process.env['GITHUB_WORKSPACE'] = '.'
+  process.env['INPUT_CONFIGURATION'] = 'configuration.json'
+  process.env['INPUT_OWNER'] = 'mikepenz'
+  process.env['INPUT_REPO'] = 'release-changelog-builder-action'
+  process.env['INPUT_FROMTAG'] = 'v0.3.0'
+  process.env['INPUT_TOTAG'] = 'v0.5.0'
+  
+  const ip = path.join(__dirname, '..', 'lib', 'main.js')
+  const options: cp.ExecSyncOptions = {
+    env: process.env
+  }
+  const result = cp.execSync(`node ${ip}`, options).toString()
+  // should succeed
+})