Enable tests for Zopfli’s non-gzip output formats (i.e. deflate and zlib)

[mathiasbynens]

So, grunt-zopfli runs fine for all kinds of output formats, and the unit tests confirm that the grunt-zopfli’s gzipped output is correct (i.e. it gunzips to the original file).

It’s highly unlikely that grunt-zopfli doesn’t work correctly for Zopfli’s deflate and zlib settings, since it uses the same code paths and everything — only the argument in the shell command is different. But it would be nice to have tests that confirm this.

The disabled tests are here:

grunt-zopfli/tests/tests.js

Lines 45 to 80 in dd6614f

	// // Test disabled because I have no idea how to decompress Zopfli-generated
	// // with the `zlib` setting. I thought `createInflateRaw` (inflate data
	// // without zlib header) would work.
	// 'test-2': function(test) {
	// test.expect(1);
	// decompress('tmp/test-2.js.zlib', 'zlib', function(actual) {
	// test.equal(
	// grunt.file.read('tests/fixtures/benchmark.js'),
	// actual,
	// 'Benchmark.js, 50 iterations, zlib format'
	// );
	// test.done();
	// });
	// },
	// 'test-3': function(test) {
	// test.expect(1);
	// decompress('tmp/test-3.js.deflate', 'deflate', function(actual) {
	// test.equal(
	// grunt.file.read('tests/fixtures/benchmark.js'),
	// actual,
	// 'Benchmark.js, 10 iterations, deflate format, perform block splitting last'
	// );
	// test.done();
	// });
	// },
	// 'test-4': function(test) {
	// test.expect(1);
	// decompress('tmp/test-4.js.deflate', 'deflate', function(actual) {
	// test.equal(
	// grunt.file.read('tests/fixtures/benchmark.js'),
	// actual,
	// 'Benchmark.js, 10 iterations, deflate format, perform block splitting first'
	// );
	// test.done();
	// });
	// },

Any ideas how to make this work? /cc @shama @aschmitz