scope-hoisting.js

const assert = require('assert');
const path = require('path');
const {bundle: _bundle, run} = require('@parcel/test-utils');
const fs = require('@parcel/fs');

const bundle = (name, opts = {}) =>
  _bundle(name, Object.assign({scopeHoist: true}, opts));

describe('scope hoisting', function() {
  describe('es6', function() {
    it('supports default imports and exports of expressions', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/default-export-expression/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports default imports and exports of declarations', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/default-export-declaration/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports default imports and exports of anonymous declarations', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/default-export-anonymous/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports default imports and exports of variables', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/default-export-variable/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports named imports and exports of declarations', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/named-export-declaration/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports named imports and exports of variables', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/named-export-variable/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports renaming superclass identifiers', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/rename-superclass/a.js'
        )
      );
      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports renaming imports', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/renamed-import/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports renaming exports', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/renamed-export/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports importing a namespace of exported values', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/import-namespace/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports re-exporting all exports from another module', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/re-export-all/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 6);
    });

    it('supports re-exporting all exports from multiple modules', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/re-export-all-multiple/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 15);
    });

    it('supports importing all exports re-exported from multiple modules deep', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/import-multiple-wildcards/a.js'
        )
      );

      let {foo, bar, baz, a, b: bb} = await run(b);
      assert.equal(foo + bar + baz + a + bb, 15);
    });

    it('supports re-exporting all exports from multiple modules deep', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/re-export-multiple/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 7);
    });

    it('supports re-exporting individual named exports from another module', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/re-export-named/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 3);
    });

    it('supports re-exporting default exports from another module', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/re-export-default/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 3);
    });

    it('supports re-exporting a namespace from another module', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/re-export-namespace/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 6);
    });

    it('excludes default when re-exporting a module', async function() {
      let threw = false;
      try {
        await bundle(
          path.join(
            __dirname,
            '/integration/scope-hoisting/es6/re-export-exclude-default/a.js'
          )
        );
      } catch (err) {
        threw = true;
        assert.equal(err.message, "b.js does not export 'default'");
      }

      assert(threw);
    });

    it('supports multiple exports of the same variable', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/multi-export/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 6);
    });

    it('supports live bindings of named exports', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/live-bindings/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 8);
    });

    it('supports dynamic import syntax for code splitting', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/dynamic-import/a.js'
        )
      );

      let output = await run(b);
      assert.equal(await output.default, 5);
    });

    it('supports nested dynamic imports', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/dynamic-import-dynamic/a.js'
        )
      );

      let output = await run(b);
      assert.equal(await output.default, 123);
    });

    it('should not export function arguments', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/export-binding-identifiers/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, ['test']);
    });

    it('throws a meaningful error on undefined exports', async function() {
      let threw = false;
      try {
        await bundle(
          path.join(
            __dirname,
            '/integration/scope-hoisting/es6/export-undefined/a.js'
          )
        );
      } catch (err) {
        threw = true;
        assert.equal(err.message, "export 'Test' is not defined");
      }

      assert(threw);
    });

    it('supports import default CommonJS interop', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/import-commonjs-default/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 'foobar');
    });

    it('supports import default CommonJS interop with dynamic imports', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/dynamic-default-interop/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(await output, 6);
    });

    it('supports exporting an import', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/re-export-var/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 'foobar');
    });

    it('supports requiring a re-exported and renamed ES6 import', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/re-export-renamed/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 'foobar');
    });

    it('keeps side effects by default', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/side-effects/a.js'
        )
      );

      let called = false;
      let output = await run(b, {
        sideEffect: () => {
          called = true;
        }
      });

      assert(called, 'side effect not called');
      assert.deepEqual(output, 4);
    });

    it('supports the package.json sideEffects: false flag', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/side-effects-false/a.js'
        )
      );

      let called = false;
      let output = await run(b, {
        sideEffect: () => {
          called = true;
        }
      });

      assert(!called, 'side effect called');
      assert.deepEqual(output, 4);
    });

    it('supports wildcards with sideEffects: false', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/side-effects-false-wildcards/a.js'
        )
      );
      let output = await run(b);

      assert.deepEqual(output, 'bar');
    });

    it('supports the package.json sideEffects flag with an array', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/side-effects-array/a.js'
        )
      );

      let calls = [];
      let output = await run(b, {
        sideEffect: caller => {
          calls.push(caller);
        }
      });

      assert(calls.toString() == 'foo', "side effect called for 'foo'");
      assert.deepEqual(output, 4);
    });

    it('missing exports should be replaced with an empty object', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/empty-module/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, {b: {}});
    });

    it('supports importing a namespace from a commonjs module when code split', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/import-namespace-commonjs/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(await output, 4);
    });

    it('removes unused exports', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/tree-shaking/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output.default, 2);

      let contents = await fs.readFile(
        path.join(__dirname, '/dist/a.js'),
        'utf8'
      );
      assert(contents.includes('foo'));
      assert(!contents.includes('bar'));
    });

    it('removes unused function exports when minified', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/tree-shaking-functions/a.js'
        ),
        {minify: true}
      );

      let output = await run(b);
      assert.deepEqual(output.default, 9);

      let contents = await fs.readFile(
        path.join(__dirname, '/dist/a.js'),
        'utf8'
      );
      assert(/.\+./.test(contents));
      assert(!/.-./.test(contents));
    });

    it('handle export multi-assignment', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/tree-shaking-multiassignment/a.js'
        ),
        {minify: true}
      );

      let output = await run(b);
      assert.deepEqual(output.default, [undefined, 'y']);

      // let contents = await fs.readFile(
      //   path.join(__dirname, '/dist/a.js'),
      //   'utf8'
      // );
      // assert(!/["']z["']/.test(contents));
    });

    it('support exporting a ES6 module exported as CommonJS', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/re-export-commonjs/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 'foo');
    });

    it('should support named imports on wrapped modules', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/import-wrapped/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 'bar');
    });

    it('should support the jsx pragma', async function() {
      let b = await bundle(
        path.join(__dirname, '/integration/scope-hoisting/es6/jsx-pragma/a.js')
      );

      let output = await run(b);
      assert.deepEqual(output, {
        children: 'Test',
        props: null,
        type: 'span'
      });
    });

    it('should not nameclash with internal variables', async function() {
      let b = await bundle(
        path.join(__dirname, '/integration/scope-hoisting/es6/name-clash/a.js')
      );

      let output = await run(b);
      assert.deepEqual(output, 'bar');
    });

    it('should shake pure property assignments', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/es6/pure-assignment/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 2);

      let contents = await fs.readFile(
        path.join(__dirname, 'dist/a.js'),
        'utf8'
      );
      assert(!/bar/.test(contents));
      assert(!/displayName/.test(contents));
    });
  });

  describe('commonjs', function() {
    it('supports require of commonjs modules', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports default imports of commonjs modules', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/default-import/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports named imports of commonjs modules', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/named-import/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports namespace imports of commonjs modules', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/import-namespace/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports require of es6 default export of expressions', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-default-export-expression/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports require of es6 default export of declarations', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-default-export-declaration/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports require of es6 default export of variables', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-default-export-variable/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports require of es6 named export of declarations', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-named-export-declaration/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports require of es6 named export of variables', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-named-export-variable/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports require of es6 renamed exports', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-renamed-export/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports require of es6 module re-exporting all exports from another module', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-re-export-all/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 6);
    });

    it('supports require of es6 module re-exporting all exports from multiple modules', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-re-export-multiple/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 7);
    });

    it('supports re-exporting individual named exports from another module', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-re-export-named/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 3);
    });

    it('supports re-exporting default exports from another module', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-re-export-default/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 3);
    });

    it('supports re-exporting a namespace from another module', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-re-export-namespace/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 6);
    });

    it('excludes default when re-exporting a module', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-re-export-exclude-default/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, {foo: 3});
    });

    it('supports hybrid ES6 + commonjs modules', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/es6-commonjs-hybrid/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 5);
    });

    it('inserts commonjs exports object in the right place', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/export-order/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 5);
    });

    it('define exports in the outermost scope', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/define-exports/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 'bar');
    });

    it('supports live bindings of named exports', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/live-bindings/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 8);
    });

    it('should wrap modules that use eval in a function', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/wrap-eval/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 4);
    });

    it('should wrap modules that have a top-level return', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/wrap-return/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('should wrap modules that access `module` as a free variable', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/wrap-module/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, {exports: {foo: 2}});
    });

    it('should wrap modules that non-statically access `module`', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/wrap-module-computed/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, {foo: 2});
    });

    it('supports assigning to this as exports object', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/this-reference/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 2);
    });

    it('supports assigning to this as exports object in wrapped module', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/this-reference-wrapped/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 6);
    });

    it('supports module object properties', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/module-object/a.js'
        )
      );

      // TODO: this test doesn't currently work in older browsers since babel
      // replaces the typeof calls before we can get to them.
      let output = await run(b);
      assert.equal(output.id, b.entryAsset.id);
      assert.equal(output.hot, null);
      assert.equal(output.type, 'object');
      assert.deepEqual(output.exports, {});
      assert.equal(output.exportsType, 'object');
      assert.equal(output.require, 'function');
    });

    it('supports require.resolve calls', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-resolve/a.js'
        )
      );

      let output = await run(b);
      assert.equal(
        output,
        Array.from(b.assets).find(a => a.name.endsWith('b.js')).id
      );
    });

    it('supports requiring a re-exported ES6 import', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/re-export-var/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 'foobar');
    });

    it('supports object pattern requires', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/object-pattern/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 5);
    });

    it('eliminates CommonJS export object where possible', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/eliminate-exports/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 6);
    });

    it('supports multiple assignments in one line', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/multi-assign/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, {foo: 2, bar: 2, baz: 2});
    });

    it('supports circular dependencies', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-circular/a.js'
        )
      );

      let output = await run(b);
      assert.equal(output, 'foo bar');
    });

    it('executes modules in the correct order', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-execution-order/a.js'
        )
      );

      let out = [];
      await run(b, {
        output(o) {
          out.push(o);
        }
      });

      assert.deepEqual(out, ['a', 'b', 'c', 'd']);
    });

    it('supports conditional requires', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-conditional/a.js'
        )
      );

      let out = [];
      await run(b, {
        b: false,
        output(o) {
          out.push(o);
        }
      });

      assert.deepEqual(out, ['a', 'd']);

      out = [];
      await run(b, {
        b: true,
        output(o) {
          out.push(o);
        }
      });

      assert.deepEqual(out, ['a', 'b', 'c', 'd']);
    });

    it('supports requires inside functions', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-in-function/a.js'
        )
      );

      let out = [];
      await run(b, {
        output(o) {
          out.push(o);
        }
      });

      assert.deepEqual(out, ['a', 'c', 'b']);
    });

    it('supports requires inside functions with es6 import side effects', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-in-function-import/a.js'
        )
      );

      let out = [];
      await run(b, {
        output(o) {
          out.push(o);
        }
      });

      assert.deepEqual(out, ['a', 'd', 'c', 'b']);
    });

    it('hoists import calls to the top', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-in-function-import-hoist/a.js'
        )
      );

      let out = [];
      await run(b, {
        output(o) {
          out.push(o);
        }
      });

      assert.deepEqual(out, ['a', 'd', 'c', 'b']);
    });

    it('supports requires inside functions with es6 re-export side effects', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/require-in-function-reexport/a.js'
        )
      );

      let out = [];
      await run(b, {
        output(o) {
          out.push(o);
        }
      });

      assert.deepEqual(out, ['a', 'd', 'c', 'b']);
    });

    it('can bundle the node stream module', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/stream-module/a.js'
        )
      );

      let res = await run(b);
      assert.equal(typeof res.Readable, 'function');
      assert.equal(typeof res.Writable, 'function');
      assert.equal(typeof res.Duplex, 'function');
    });

    it('missing exports should be replaced with an empty object', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/empty-module/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, {b: {}});
    });

    it('removes unused exports', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/tree-shaking/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 2);

      let contents = await fs.readFile(
        path.join(__dirname, '/dist/a.js'),
        'utf8'
      );
      assert(contents.includes('foo'));
      assert(!contents.includes('bar'));
    });

    it('supports removing an unused inline export with uglify minification', async function() {
      // Uglify does strange things to multiple assignments in a line.
      // See https://github.com/parcel-bundler/parcel/issues/1549
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/export-local/a.js'
        ),
        {minify: true}
      );

      let output = await run(b);
      assert.deepEqual(output, 3);
    });

    it('should support sideEffects: false', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/side-effects-false/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 9);
    });

    it('should support two aliases to the same module', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/wrap-aliases/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 42);
    });

    it('should support optional requires', async function() {
      let b = await bundle(
        path.join(
          __dirname,
          '/integration/scope-hoisting/commonjs/wrap-optional/a.js'
        )
      );

      let output = await run(b);
      assert.deepEqual(output, 42);
    });
  });
});