modify read log util and make a single test pass by adding blocking code

test/cli/steps.js

@@ -0,0 +1,37 @@
+const test = require('tape');
+const cli = require('../../src/cli');
+const stdout = require('./util/readConsole').stdout;
+const stderr = require('./util/readConsole').stderr;
+
+function sleep(ms) {
+  return new Promise(resolve => setTimeout(resolve, ms));
+}
+
+test('testing steps parsing', function (t) {
+
+  t.plan(1);
+
+  let out = stdout.read();
+
+  cli([
+    'node', 'test',
+    '-i', 'examples/images/test.png',
+    '-s', 'invert',
+  ]);
+
+  sleep(1000).then(() => {
+    out.restore();
+    let validator = out.output().includes('Added Step "invert"');
+    t.true(validator, 'Steps parsed successfully');
+  });
+
+
+//   let err = stderr.read();
+//   await cli([
+//     'node', 'test',
+//     '-i', 'examples/images/test.png',
+//     '-s', 'invalidStep',
+//   ]);
+//   err.restore();
+//   t.equal(err.output, 'Please ensure all steps are valid.');
+});

test/cli/util/readConsole.js

@@ -0,0 +1,26 @@
+function ReadLog(stream) {
+  this._stream = stream;
+}
+
+ReadLog.prototype.read = function(options) {
+    
+  let output = '';
+  let stream = this._stream;
+    
+  let originalStreamWrite = stream.write;
+  stream.write = function(string) {
+    output += string;
+  };
+    
+  return {
+    output: function () {
+      return output;
+    },
+    restore: function() {
+      stream.write = originalStreamWrite;
+    }
+  };
+};
+
+exports.stdout = new ReadLog(process.stdout);
+exports.stderr = new ReadLog(process.stderr);