test: add a smoke test that builds _all_ formats

- there was never a test that built all, meaning tests left out the
  somewhat popular UMD build in particular
  - per my investigation, CJS + UMD, CJS + System, UMD + System started
    bugging out recently due to an upstream bug, but this wasn't known
    proactively because there were no tests for it
    - and I also found that CJS + System actually was bugging out in
      the previous version, TSDX v0.13.3, but I'm guessing no one
      reported it back then as it's an unpopular combination of formats

- this test fails prior to upgrade of rpts2 to v0.27.3 and succeeds
  after the upgrade
  - so this should act as a regression test against this bug as well

- created a new e2e build-options test file for this because
  build-default is meant to have 0 options and test only the defaults
  - had to give it a differentiated "stage" name as it uses the same
    build-default fixture and so breaks during test parallelization
    without that
  - should also move the regeneratorRuntime `--target node` test here
    since that's an option and not a default

test/e2e/tsdx-build-options.test.ts

@@ -0,0 +1,53 @@
+import * as shell from 'shelljs';
+
+import * as util from '../utils/fixture';
+import { execWithCache } from '../utils/shell';
+
+shell.config.silent = false;
+
+const testDir = 'e2e';
+const fixtureName = 'build-default';
+// create a second version of build-default's stage for concurrent testing
+const stageName = 'stage-build-options';
+
+describe('tsdx build :: options', () => {
+  beforeAll(() => {
+    util.teardownStage(stageName);
+    util.setupStageWithFixture(testDir, stageName, fixtureName);
+  });
+
+  it('should compile all formats', () => {
+    const output = execWithCache(
+      'node ../dist/index.js build --format cjs,esm,umd,system'
+    );
+
+    expect(shell.test('-f', 'dist/index.js')).toBeTruthy();
+    expect(
+      shell.test('-f', 'dist/build-default.cjs.development.js')
+    ).toBeTruthy();
+    expect(
+      shell.test('-f', 'dist/build-default.cjs.production.min.js')
+    ).toBeTruthy();
+    expect(shell.test('-f', 'dist/build-default.esm.js')).toBeTruthy();
+    expect(
+      shell.test('-f', 'dist/build-default.umd.development.js')
+    ).toBeTruthy();
+    expect(
+      shell.test('-f', 'dist/build-default.umd.production.min.js')
+    ).toBeTruthy();
+    expect(
+      shell.test('-f', 'dist/build-default.system.development.js')
+    ).toBeTruthy();
+    expect(
+      shell.test('-f', 'dist/build-default.system.production.min.js')
+    ).toBeTruthy();
+
+    expect(shell.test('-f', 'dist/index.d.ts')).toBeTruthy();
+
+    expect(output.code).toBe(0);
+  });
+
+  afterAll(() => {
+    util.teardownStage(stageName);
+  });
+});