Add 'list all reviews' endpoint from new pull request review API

This commit adds only one of the total 6 endpoints made available
for developers preview.

Partly fixes #495

EDIT: Fix minor things based on initial review.

Author: sahildua2305

github/github.go

@@ -91,6 +91,9 @@ const (
 
 	// https://developer.github.com/changes/2016-09-14-Integrations-Early-Access/
 	mediaTypeIntegrationPreview = "application/vnd.github.machine-man-preview+json"
+
+	// https://developer.github.com/changes/2016-12-14-reviews-api/
+	mediaTypePullRequestReviewsPreview = "application/vnd.github.black-cat-preview+json"
 )
 
 // A Client manages communication with the GitHub API.

github/pulls_reviews.go

@@ -5,15 +5,48 @@
 
 package github
 
-import "time"
+import (
+	"fmt"
+	"time"
+)
 
 // PullRequestReview represents a review of a pull request.
 type PullRequestReview struct {
-	ID          *int       `json:"id,omitempty"`
-	User        *User      `json:"user,omitempty"`
-	Body        *string    `json:"body,omitempty"`
-	SubmittedAt *time.Time `json:"submitted_at,omitempty"`
+	ID             *int       `json:"id,omitempty"`
+	User           *User      `json:"user,omitempty"`
+	Body           *string    `json:"body,omitempty"`
+	SubmittedAt    *time.Time `json:"submitted_at,omitempty"`
+	CommitID       *string    `json:"commit_id,omitempty"`
+	HTMLURL        *string    `json:"html_url,omitempty"`
+	PullRequestURL *string    `json:"pull_request_url,omitempty"`
 
-	// State can be "approved", "rejected", or "commented".
+	// State can be "ACCEPTED", "DISMISSED", "CHANGES_REQUESTED" or "COMMENTED".
 	State *string `json:"state,omitempty"`
 }
+
+func (p PullRequestReview) String() string {
+	return Stringify(p)
+}
+
+// ListReviews lists all reviews on the specified pull request.
+//
+// GitHub API docs: https://developer.github.com/v3/pulls/reviews/#list-reviews-on-a-pull-request
+func (s *PullRequestsService) ListReviews(owner string, repo string, number int) ([]*PullRequestReview, *Response, error) {
+	u := fmt.Sprintf("repos/%v/%v/pulls/%d/reviews", owner, repo, number)
+
+	req, err := s.client.NewRequest("GET", u, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// TODO: remove custom Accept header when this API fully launches
+	req.Header.Set("Accept", mediaTypePullRequestReviewsPreview)
+
+	reviews := new([]*PullRequestReview)
+	resp, err := s.client.Do(req, reviews)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return *reviews, resp, err
+}

github/pulls_reviews_test.go

@@ -0,0 +1,37 @@
+// Copyright 2016 The go-github AUTHORS. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package github
+
+import (
+	"fmt"
+	"net/http"
+	"reflect"
+	"testing"
+)
+
+func TestPullRequestsService_ListReviews(t *testing.T) {
+	setup()
+	defer teardown()
+
+	mux.HandleFunc("/repos/o/r/pulls/1/reviews", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "GET")
+		testHeader(t, r, "Accept", mediaTypePullRequestReviewsPreview)
+		fmt.Fprint(w, `[{"id":1},{"id":2}]`)
+	})
+
+	reviews, _, err := client.PullRequests.ListReviews("o", "r", 1)
+	if err != nil {
+		t.Errorf("PullRequests.ListReviews returned error: %v", err)
+	}
+
+	want := []*PullRequestReview{
+		{ID: Int(1)},
+		{ID: Int(2)},
+	}
+	if !reflect.DeepEqual(reviews, want) {
+		t.Errorf("PullRequests.ListReviews returned %+v, want %+v", reviews, want)
+	}
+}