Add support for Commit Search endpoint

Added support for this new preview endpoint which lets users
search for commits based on various conditions.

GitHub announcement -
https://developer.github.com/changes/2017-01-05-commit-search-api/
Docs - https://developer.github.com/v3/search/#search-commits

Fixes #508.
Closes #520.

Change-Id: I2210fafe3da530716075f9113851e09e3bc671f8

Author: sahildua2305

github/github.go

@@ -93,6 +93,9 @@ const (
 
 	// https://developer.github.com/changes/2016-11-28-preview-org-membership/
 	mediaTypeOrgMembershipPreview = "application/vnd.github.korra-preview+json"
+
+	// https://developer.github.com/changes/2017-01-05-commit-search-api/
+	mediaTypeCommitSearchPreview = "application/vnd.github.cloak-preview+json"
 )
 
 // A Client manages communication with the GitHub API.

github/search.go

@@ -21,6 +21,7 @@ type SearchService service
 type SearchOptions struct {
 	// How to sort the search results.  Possible values are:
 	//   - for repositories: stars, fork, updated
+	//   - for commits: author-date, committer-date
 	//   - for code: indexed
 	//   - for issues: comments, created, updated
 	//   - for users: followers, repositories, joined
@@ -54,6 +55,37 @@ func (s *SearchService) Repositories(query string, opt *SearchOptions) (*Reposit
 	return result, resp, err
 }
 
+// CommitsSearchResult represents the result of a commits search.
+type CommitsSearchResult struct {
+	Total             *int            `json:"total_count,omitempty"`
+	IncompleteResults *bool           `json:"incomplete_results,omitempty"`
+	Commits           []*CommitResult `json:"items,omitempty"`
+}
+
+// CommitResult represents a commit object as returned in commit search endpoint response.
+type CommitResult struct {
+	Hash           *string     `json:"hash,omitempty"`
+	Message        *string     `json:"message,omitempty"`
+	AuthorID       *int        `json:"author_id,omitempty"`
+	AuthorName     *string     `json:"author_name,omitempty"`
+	AuthorEmail    *string     `json:"author_email,omitempty"`
+	AuthorDate     *Timestamp  `json:"author_date,omitempty"`
+	CommitterID    *int        `json:"committer_id,omitempty"`
+	CommitterName  *string     `json:"committer_name,omitempty"`
+	CommitterEmail *string     `json:"committer_email,omitempty"`
+	CommitterDate  *Timestamp  `json:"committer_date,omitempty"`
+	Repository     *Repository `json:"repository,omitempty"`
+}
+
+// Commits searches commits via various criteria.
+//
+// GitHub API Docs: https://developer.github.com/v3/search/#search-commits
+func (s *SearchService) Commits(query string, opt *SearchOptions) (*CommitsSearchResult, *Response, error) {
+	result := new(CommitsSearchResult)
+	resp, err := s.search("commits", query, opt, result)
+	return result, resp, err
+}
+
 // IssuesSearchResult represents the result of an issues search.
 type IssuesSearchResult struct {
 	Total             *int    `json:"total_count,omitempty"`
@@ -136,7 +168,7 @@ func (s *SearchService) Code(query string, opt *SearchOptions) (*CodeSearchResul
 }
 
 // Helper function that executes search queries against different
-// GitHub search types (repositories, code, issues, users)
+// GitHub search types (repositories, commits, code, issues, users)
 func (s *SearchService) search(searchType string, query string, opt *SearchOptions, result interface{}) (*Response, error) {
 	params, err := qs.Values(opt)
 	if err != nil {
@@ -150,7 +182,12 @@ func (s *SearchService) search(searchType string, query string, opt *SearchOptio
 		return nil, err
 	}
 
-	if opt != nil && opt.TextMatch {
+	switch {
+	case searchType == "commits":
+		// Accept header for search commits preview endpoint
+		// TODO: remove custom Accept header when this API fully launches.
+		req.Header.Set("Accept", mediaTypeCommitSearchPreview)
+	case opt != nil && opt.TextMatch:
 		// Accept header defaults to "application/vnd.github.v3+json"
 		// We change it here to fetch back text-match metadata
 		req.Header.Set("Accept", "application/vnd.github.v3.text-match+json")

github/search_test.go

@@ -46,6 +46,37 @@ func TestSearchService_Repositories(t *testing.T) {
 	}
 }
 
+func TestSearchService_Commits(t *testing.T) {
+	setup()
+	defer teardown()
+
+	mux.HandleFunc("/search/commits", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "GET")
+		testFormValues(t, r, values{
+			"q":     "blah",
+			"sort":  "author-date",
+			"order": "desc",
+		})
+
+		fmt.Fprint(w, `{"total_count": 4, "incomplete_results": false, "items": [{"hash":"random_hash1"},{"hash":"random_hash2"}]}`)
+	})
+
+	opts := &SearchOptions{Sort: "author-date", Order: "desc"}
+	result, _, err := client.Search.Commits("blah", opts)
+	if err != nil {
+		t.Errorf("Search.Commits returned error: %v", err)
+	}
+
+	want := &CommitsSearchResult{
+		Total:             Int(4),
+		IncompleteResults: Bool(false),
+		Commits:           []*CommitResult{{Hash: String("random_hash1")}, {Hash: String("random_hash2")}},
+	}
+	if !reflect.DeepEqual(result, want) {
+		t.Errorf("Search.Commits returned %+v, want %+v", result, want)
+	}
+}
+
 func TestSearchService_Issues(t *testing.T) {
 	setup()
 	defer teardown()