Module tests (#1058)

* change all old module benchmarks

* no node 6

* add average module tests

* edge-detect test added

* edge detect tests

* flip-image tests

* tint tests

* saturation tests

* gradient tests

* exposure tests

* draw-rectangle tests

* color-temperature tests

* convolution tests

* paint-bucket tests

* ndvi tests

* ndvi-colormap tests

* histogram tests

* crop tests

* gamma-correction tests

* dynamic tests

* colorbar tests

* webgl-distort tests

* fisheye-gl tests

* blend module tests

* overlay module tests

test/core/templates/module-test.js

@@ -0,0 +1,58 @@
+const test = require('tape'),
+  base64Img = require('base64-img'),
+  looksSame = require('looks-same');
+
+const ImageSequencer = require('../../../src/ImageSequencer')
+
+const red = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQAQMAAAAlPW0iAAAABGdBTUEAALGPC/xhBQAAACBjSFJNAAB6JgAAgIQAAPoAAACA6AAAdTAAAOpgAAA6mAAAF3CculE8AAAABlBMVEX+AAD///+KQee0AAAAAWJLR0QB/wIt3gAAAAd0SU1FB+EGHRIVAvrm6EMAAAAMSURBVAjXY2AgDQAAADAAAceqhY4AAAAldEVYdGRhdGU6Y3JlYXRlADIwMTctMDYtMjlUMTg6MjE6MDIrMDI6MDDGD83DAAAAJXRFWHRkYXRlOm1vZGlmeQAyMDE3LTA2LTI5VDE4OjIxOjAyKzAyOjAwt1J1fwAAAABJRU5ErkJggg=="
+  target = 'test_outputs';
+
+/**
+ * @method moduleTest
+ * @description a common test for modules
+ * @param {String} moduleName name of the module
+ * @param {"Object"} options module options
+ * @param {String} benchmark dataURI of the benchmark image
+ * @param {String} [input="red_image"] optional input image. Default is a red image.
+ */
+module.exports = (moduleName, options, benchmark, input) => {
+  let sequencer = ImageSequencer({ui: false})
+
+  test(`${moduleName} module loads correctly`, t => {
+    sequencer.loadImages(input || red)
+    sequencer.addSteps(moduleName, options)
+
+    t.equal(sequencer.steps[1].options.name, moduleName, `${moduleName} module is getting loaded`)
+    t.end()
+  })
+
+  test(`${moduleName} module loads with correct options`, t => {
+    for (const option in options) {
+      t.equal(sequencer.steps[1].options[option], options[option], `Option ${option} is correct`)
+    }
+
+    t.end();
+  })
+
+  test(`${moduleName} module works correctly`, t => {
+    sequencer.run({mode: 'test'}, () => {
+
+      let result = sequencer.steps[1].output.src
+
+      base64Img.imgSync(result, target, 'result')
+      base64Img.imgSync(benchmark, target, 'benchmark')
+
+      result = './test_outputs/result.png'
+      benchmark = './test_outputs/benchmark.png'
+
+      looksSame(result, benchmark, function(err, res) {
+        if (err) console.log(err)
+
+        t.equal(res.equal, true, `${moduleName} module works correctly`)
+        sequencer = null
+        t.end()
+      })
+    })
+  })
+  
+}