Add error-utils helper and tests

src/error-utils.test.js

@@ -0,0 +1,38 @@
+const { convertErrorToAnnotationProperties } = require('./error-utils')
+
+describe('error-utils', () => {
+  describe('convertErrorToAnnotationProperties', () => {
+    it('throws a TypeError if the first argument is not an Error instance', () => {
+      expect(() => convertErrorToAnnotationProperties('not an Error')).toThrow(
+        TypeError,
+        'error must be an instance of Error'
+      )
+    })
+
+    it('throws an Error if the first argument is an Error instance without a parseable stack', () => {
+      const error = new Error('Test error')
+      error.stack = ''
+      expect(() => convertErrorToAnnotationProperties(error)).toThrow(Error, 'Error stack is empty or unparseable')
+    })
+
+    it('returns an AnnotationProperties-compatible object', () => {
+      const result = convertErrorToAnnotationProperties(new TypeError('Test error'))
+      expect(result).toEqual({
+        title: 'TypeError',
+        file: __filename,
+        startLine: expect.any(Number),
+        startColumn: expect.any(Number)
+      })
+    })
+
+    it('returns an AnnotationProperties-compatible object with a custom title', () => {
+      const result = convertErrorToAnnotationProperties(new TypeError('Test error'), 'custom title')
+      expect(result).toEqual({
+        title: 'custom title',
+        file: __filename,
+        startLine: expect.any(Number),
+        startColumn: expect.any(Number)
+      })
+    })
+  })
+})