fix(tests): ensure jest respects passed flags (#3329)

this commit updates the jest argument builder to
respect updates to flags passed to jest. legacy jest
options would previously overwrite options that a
user passed in via the command line. by reordering
the input to the jest arguments, cli arguments are now
respected

src/testing/jest/jest-config.ts

@@ -59,7 +59,7 @@ export function buildJestArgv(config: d.Config): Config.Argv {
   config.logger.info(config.logger.magenta(`jest args: ${args.join(' ')}`));
 
   let jestArgv = yargs(args).argv as Config.Argv;
-  jestArgv = { ...jestArgv, ...getLegacyJestOptions() };
+  jestArgv = { ...getLegacyJestOptions(), ...jestArgv };
   jestArgv.config = buildJestConfig(config);
 
   if (typeof jestArgv.maxWorkers === 'string') {

src/testing/jest/test/jest-config.spec.ts

@@ -178,4 +178,18 @@ describe('jest-config', () => {
     expect(parsedConfig.collectCoverageFrom).toHaveLength(1);
     expect(parsedConfig.collectCoverageFrom[0]).toBe('**/*.+(ts|tsx)');
   });
+
+  it('passed flags should be respected over defaults', () => {
+    const args = ['test', '--spec', '--passWithNoTests'];
+    const config = mockConfig();
+    config.flags = parseFlags(args, config.sys);
+    config.testing = {};
+
+    expect(config.flags.args).toEqual(['--spec', '--passWithNoTests']);
+    expect(config.flags.unknownArgs).toEqual(['--passWithNoTests']);
+
+    const jestArgv = buildJestArgv(config);
+    expect(jestArgv.spec).toBe(true);
+    expect(jestArgv.passWithNoTests).toBe(true);
+  });
 });