Initial work on the CHANGELOG test, and adds a fail command

changelog.md

@@ -0,0 +1,51 @@
+### 0.0.2 
+
+OK, first usable for others version. Only supports GitHub and Travis CI.
+
+You can run by doing:
+
+```sh
+danger
+``` 
+
+Make sure you set a `DANGER_GITHUB_API_TOKEN` on your CI - [see the Ruby guide](http://danger.systems/guides/getting_started.html#setting-up-danger-to-run-on-your-ci) for that.
+
+Then you can make a `dangerfile.js` (has to be lowercase, deal with it.) It has access to a whopping 2 DSL attributes.
+
+```sh
+pr
+git
+fail(message: string)
+```
+
+`pr` _probably_ won't be sticking around for the long run, but if you're using a `0.0.2` release, you should be OK with that. It's the full metadata of the PR, so [this JSON file](https://raw.githubusercontent.com/danger/danger/master/spec/fixtures/github_api/pr_response.json). 
+`git` currently has:
+
+```sh
+git.modified_file
+git.created_files
+git.deleted_files 
+```
+
+which are string arrays of files.
+
+`fail(message: string)` will let you raise an error, and will make the process return 1 after the parsing has finished.
+
+Overall: your Dangerfile should look something like:
+
+```js
+import { danger } from "danger"
+
+const hasChangelog = danger.git.modified_files.includes("changelog.md")
+if (!hasChangelog) {
+  fail("No Changelog changes!")
+}
+```
+
+That should do ya. I think. This doens't support babel, and I haven't explored using other modules etc, so 
+
+./
+
+### 0.0.1
+
+Not usable for others, only stubs of classes etc.

dangerfile.js

@@ -1,9 +1,13 @@
 // @flow
 
 // import danger from "danger"
-import danger from "./source/danger"
+import { danger, fail } from "./source/danger"
 
 // warn on changes in Package.json and not in shrinkwrap
+const hasChangelog = danger.git.modified_files.includes("changelog.md")
+if (!hasChangelog) {
+  fail("No Changelog changes!")
+}
 
 // warn on changelog
 // console.log(danger)

source/danger.js

@@ -12,12 +12,14 @@ type DangerDSL = {
   git: GitDSL
 }
 
-const danger: DangerDSL = {
+/** Fails the build */
+export function fail(message: string) {
+}
+
+export const danger: DangerDSL = {
   git: {
     modified_files: ["hello world"],
     created_files: ["other file"],
     deleted_files: ["last file"]
   }
 }
-
-export default danger

source/dsl/DangerDSL.js

@@ -1,7 +1,6 @@
 // @flow
 "use strict"
 
-// import type { Platform } from "../platforms/platform"
 import type { GitDSL } from "../dsl/Git"
 
 export default class DangerDSL {

source/runner/Dangerfile.js

@@ -18,7 +18,9 @@ export default class Dangerfile {
       // then user get typed data, and we fill it in
       // via the VM context
 
-      const cleaned = data.replace(/import danger from/gi, "// import danger from")
+      const cleaned = data
+        .replace(/import danger /gi, "// import danger ")
+        .replace(/import { danger/gi, "// import { danger ")
 
       const script = new vm.Script(cleaned, {
         filename: file,
@@ -28,12 +30,20 @@ export default class Dangerfile {
         timeout: 1000 // ms
       })
 
+      let failed = false
+      const fail = (message: string) => {
+        console.error(message)
+        failed = true
+      }
+
       const context: any = {
+        fail,
         console,
         danger: this.dsl
       }
 
       script.runInNewContext(context)
+      if (failed) { process.exitCode = 1 }
     })
   }
 }