(refactor): even better multi-entry test errors w/ toMatchObject

- output is now like:
  Object {
    -   "foo.cjs.development.js": true,
    -   "foo.cjs.production.min.js": true,
        "foo.d.ts": true,
    -   "foo.esm.js": true,
    -   "foo.js": true,
        "index.cjs.development.js": true,
        "index.cjs.production.min.js": true,
        "index.d.ts": true,
        "index.esm.js": true,
        "index.js": true,
  }
  - super readable!!
  - and no extraneous files listed (e.g. .map, other directories, etc)

test/tests/tsdx-build.test.js

@@ -43,23 +43,27 @@ describe('tsdx build', () => {
       '--entry src/subdir1/subdir1-2/index.ts',
       '--entry src/**/*.ts',
       '--format esm,cjs'].join(' '));
+    const outputFiles = shell.ls('-R', 'dist/');
 
-    function testEntryOutput (filename) {
-      expect(shell.test('-f', `dist/${filename}.js`)).toBeTruthy();
-      expect(
-        shell.test('-f', `dist/${filename}.cjs.development.js`)
-      ).toBeTruthy();
-      expect(
-        shell.test('-f', `dist/${filename}.cjs.production.min.js`)
-      ).toBeTruthy();
-      expect(shell.test('-f', `dist/${filename}.esm.js`)).toBeTruthy();
-      expect(shell.test('-f', `dist/${filename}.d.ts`)).toBeTruthy();
+    function arrToDict (arr) {
+      return arr.reduce((dict, elem) => {
+        dict[elem] = true;
+        return dict;
+      }, {});
     }
-
-    testEntryOutput('index')
-    testEntryOutput('foo')
-    testEntryOutput('subdir1/subdir1-2/index')
-    testEntryOutput('subdir1/glob')
+    const outputDict = arrToDict(outputFiles);
+
+    const entries = ['index', 'foo', 'subdir1/subdir1-2/index', 'subdir1/glob'];
+    const expected = entries.reduce((dict, entry) => {
+      dict[`${entry}.js`] = true;
+      dict[`${entry}.cjs.development.js`] = true;
+      dict[`${entry}.cjs.production.min.js`] = true;
+      dict[`${entry}.esm.js`] = true;
+      dict[`${entry}.d.ts`] = true;
+      return dict;
+    }, {});
+
+    expect(outputDict).toMatchObject(expected);
 
     expect(output.code).toBe(0);
   });