adds test for optional progress function

package.json

@@ -50,6 +50,7 @@
     "pull-generate": "^2.2.0",
     "pull-zip": "^2.0.1",
     "rimraf": "^2.6.1",
+    "sinon": "^3.2.1",
     "split": "^1.0.0"
   },
   "dependencies": {
@@ -90,4 +91,4 @@
     "jbenet <juan@benet.ai>",
     "nginnever <ginneversource@gmail.com>"
   ]
-}
+}

test/test-importer.js

@@ -7,6 +7,7 @@ const extend = require('deep-extend')
 const chai = require('chai')
 chai.use(require('dirty-chai'))
 const expect = chai.expect
+const sinon = require('sinon')
 const BlockService = require('ipfs-block-service')
 const pull = require('pull-stream')
 const mh = require('multihashes')
@@ -417,6 +418,37 @@ module.exports = (repo) => {
           }
         }
       })
+
+      it('will call a progress function', (done) => {
+        options.progress = sinon.spy()
+        pull(
+          pull.values([{
+            path: '1.2MiB.txt',
+            content: pull.values([bigFile])
+          }]),
+          importer(ipldResolver, options),
+          pull.collect(() => {
+            expect(options.progress.called).to.be.true
+            expect(options.progress.args[0][0]).to.equal(1024)
+            done()
+          })
+        )
+      })
+
+      it('only if it is passed', (done) => {
+        options.progress = false
+        pull(
+          pull.values([{
+            path: '200Bytes.txt',
+            content: pull.values([smallFile])
+          }]),
+          importer(ipldResolver, options),
+          pull.collect(() => {
+            expect(options.progress.notCalled).to.be.true
+            done()
+          })
+        )
+      })
     })
   })
 }