fix: Add tests for deprecation warning

Author: thomasrockhu

test/fixtures/invalid_yaml/codecov.yaml

@@ -0,0 +1 @@
+codecov_token: faketoken

test/helpers/token.test.js

@@ -1,4 +1,5 @@
 const path = require('path')
+const { expect, it } = require('@jest/globals')
 
 const fileHelpers = require('../../src/helpers/files')
 const tokenHelpers = require('../../src/helpers/token')
@@ -8,7 +9,15 @@ describe('Get tokens', () => {
     fileHelpers.fetchGitRoot(),
     'test/fixtures/yaml',
   )
-  console.log(fixturesDir)
+  const invalidFixturesDir = path.join(
+    fileHelpers.fetchGitRoot(),
+    'test/fixtures/invalid_yaml',
+  )
+
+  afterEach(() => {
+    jest.clearAllMocks()
+  })
+
   describe('From yaml', () => {
     it('Returns empty with no yaml file', () => {
       expect(tokenHelpers.getTokenFromYaml('.')).toBe('')
@@ -19,6 +28,19 @@ describe('Get tokens', () => {
         tokenHelpers.getTokenFromYaml(fixturesDir, { verbose: true }),
       ).toBe('faketoken')
     })
+
+    it('Returns deprecation error from codecov_token', () => {
+      jest.spyOn(console, 'error').mockImplementation(() => {
+        // Intentionally empty
+      })
+      expect(
+        tokenHelpers.getTokenFromYaml(invalidFixturesDir, { verbose: true }),
+      ).toBe('')
+
+      expect(console.error).toHaveBeenCalledWith(
+        expect.stringContaining("'codecov_token' is a deprecated field"),
+      )
+    })
   })
 
   describe('From right source', () => {