tests: add tests for error codes

src/app/modules/core/__tests__/core.errors.spec.ts

@@ -0,0 +1,28 @@
+import { ErrorCodes } from '../core.errors'
+
+describe('core', () => {
+  describe('error codes', () => {
+    it('should be 6 digits long', () => {
+      // iterate through the enum values and verify that they are 6 digits
+      // not the value but the length of the number representation
+      const errorCodeValues = Object.values(ErrorCodes).filter(
+        (value) => typeof value === 'number',
+      ) as number[]
+
+      errorCodeValues.forEach((errorCode) => {
+        expect(String(errorCode).length).toBe(6)
+      })
+    })
+
+    it('should follow SCREAMING_SNAKE_CASE', () => {
+      const isScreamingSnakeCase = /^[A-Z0-9]+(_[A-Z0-9]+)*$/
+
+      // TS enums put both the key and the value in the enum object
+      const keys = Object.keys(ErrorCodes).filter((v) => isNaN(Number(v)))
+
+      keys.forEach((key) => {
+        expect(key).toMatch(isScreamingSnakeCase)
+      })
+    })
+  })
+})