Adds required pull request reviews

`required_pull_request_reviews` is a newly introduced object:
* https://developer.github.com/v3/repos/branches/#get-branch-protection
* https://developer.github.com/v3/repos/branches/#update-branch-protection

Closes google#512.

Change-Id: Ia4d3ff3e39163fe58a691a8abf0a067bf3c714e5

Author: alindeman

github/repos.go

@@ -508,34 +508,42 @@ type Branch struct {
 
 // Protection represents a repository branch's protection.
 type Protection struct {
-	RequiredStatusChecks *RequiredStatusChecks `json:"required_status_checks"`
-	Restrictions         *BranchRestrictions   `json:"restrictions"`
+	RequiredStatusChecks       *RequiredStatusChecks       `json:"required_status_checks"`
+	RequiredPullRequestReviews *RequiredPullRequestReviews `json:"required_pull_request_reviews"`
+	Restrictions               *BranchRestrictions         `json:"restrictions"`
 }
 
 // ProtectionRequest represents a request to create/edit a branch's protection.
 type ProtectionRequest struct {
-	RequiredStatusChecks *RequiredStatusChecks      `json:"required_status_checks"`
-	Restrictions         *BranchRestrictionsRequest `json:"restrictions"`
+	RequiredStatusChecks       *RequiredStatusChecks       `json:"required_status_checks"`
+	RequiredPullRequestReviews *RequiredPullRequestReviews `json:"required_pull_request_reviews"`
+	Restrictions               *BranchRestrictionsRequest  `json:"restrictions"`
 }
 
 // RequiredStatusChecks represents the protection status of a individual branch.
 type RequiredStatusChecks struct {
 	// Enforce required status checks for repository administrators.
-	IncludeAdmins *bool `json:"include_admins,omitempty"`
+	IncludeAdmins bool `json:"include_admins"`
 	// Require branches to be up to date before merging.
-	Strict *bool `json:"strict,omitempty"`
+	Strict bool `json:"strict"`
 	// The list of status checks to require in order to merge into this
 	// branch.
-	Contexts *[]string `json:"contexts,omitempty"`
+	Contexts []string `json:"contexts"`
+}
+
+// RequiredPullRequestReviews represents the protection configuration for pull requests.
+type RequiredPullRequestReviews struct {
+	// Enforce pull request reviews for repository administrators.
+	IncludeAdmins bool `json:"include_admins"`
 }
 
 // BranchRestrictions represents the restriction that only certain users or
 // teams may push to a branch.
 type BranchRestrictions struct {
 	// The list of user logins with push access.
-	Users []*User `json:"users,omitempty"`
+	Users []*User `json:"users"`
 	// The list of team slugs with push access.
-	Teams []*Team `json:"teams,omitempty"`
+	Teams []*Team `json:"teams"`
 }
 
 // BranchRestrictionsRequest represents the request to create/edit the
@@ -544,9 +552,9 @@ type BranchRestrictions struct {
 // different from the response structure.
 type BranchRestrictionsRequest struct {
 	// The list of user logins with push access.
-	Users *[]string `json:"users,omitempty"`
+	Users []string `json:"users"`
 	// The list of team slugs with push access.
-	Teams *[]string `json:"teams,omitempty"`
+	Teams []string `json:"teams"`
 }
 
 // ListBranches lists branches for the specified repository.

github/repos_test.go

@@ -481,7 +481,7 @@ func TestRepositoriesService_GetBranchProtection(t *testing.T) {
 
 		testMethod(t, r, "GET")
 		testHeader(t, r, "Accept", mediaTypeProtectedBranchesPreview)
-		fmt.Fprintf(w, `{"required_status_checks":{"include_admins":true,"strict":true,"contexts":["continuous-integration"]},"restrictions":{"users":[{"id":1,"login":"u"}],"teams":[{"id":2,"slug":"t"}]}}`)
+		fmt.Fprintf(w, `{"required_status_checks":{"include_admins":true,"strict":true,"contexts":["continuous-integration"]},"required_pull_request_reviews":{"include_admins":true},"restrictions":{"users":[{"id":1,"login":"u"}],"teams":[{"id":2,"slug":"t"}]}}`)
 	})
 
 	protection, _, err := client.Repositories.GetBranchProtection("o", "r", "b")
@@ -491,9 +491,12 @@ func TestRepositoriesService_GetBranchProtection(t *testing.T) {
 
 	want := &Protection{
 		RequiredStatusChecks: &RequiredStatusChecks{
-			IncludeAdmins: Bool(true),
-			Strict:        Bool(true),
-			Contexts:      &[]string{"continuous-integration"},
+			IncludeAdmins: true,
+			Strict:        true,
+			Contexts:      []string{"continuous-integration"},
+		},
+		RequiredPullRequestReviews: &RequiredPullRequestReviews{
+			IncludeAdmins: true,
 		},
 		Restrictions: &BranchRestrictions{
 			Users: []*User{
@@ -515,13 +518,16 @@ func TestRepositoriesService_UpdateBranchProtection(t *testing.T) {
 
 	input := &ProtectionRequest{
 		RequiredStatusChecks: &RequiredStatusChecks{
-			IncludeAdmins: Bool(true),
-			Strict:        Bool(true),
-			Contexts:      &[]string{"continuous-integration"},
+			IncludeAdmins: true,
+			Strict:        true,
+			Contexts:      []string{"continuous-integration"},
+		},
+		RequiredPullRequestReviews: &RequiredPullRequestReviews{
+			IncludeAdmins: true,
 		},
 		Restrictions: &BranchRestrictionsRequest{
-			Users: &[]string{"u"},
-			Teams: &[]string{"t"},
+			Users: []string{"u"},
+			Teams: []string{"t"},
 		},
 	}
 
@@ -534,7 +540,7 @@ func TestRepositoriesService_UpdateBranchProtection(t *testing.T) {
 			t.Errorf("Request body = %+v, want %+v", v, input)
 		}
 		testHeader(t, r, "Accept", mediaTypeProtectedBranchesPreview)
-		fmt.Fprintf(w, `{"required_status_checks":{"include_admins":true,"strict":true,"contexts":["continuous-integration"]},"restrictions":{"users":[{"id":1,"login":"u"}],"teams":[{"id":2,"slug":"t"}]}}`)
+		fmt.Fprintf(w, `{"required_status_checks":{"include_admins":true,"strict":true,"contexts":["continuous-integration"]},"required_pull_request_reviews":{"include_admins":true},"restrictions":{"users":[{"id":1,"login":"u"}],"teams":[{"id":2,"slug":"t"}]}}`)
 	})
 
 	protection, _, err := client.Repositories.UpdateBranchProtection("o", "r", "b", input)
@@ -544,9 +550,12 @@ func TestRepositoriesService_UpdateBranchProtection(t *testing.T) {
 
 	want := &Protection{
 		RequiredStatusChecks: &RequiredStatusChecks{
-			IncludeAdmins: Bool(true),
-			Strict:        Bool(true),
-			Contexts:      &[]string{"continuous-integration"},
+			IncludeAdmins: true,
+			Strict:        true,
+			Contexts:      []string{"continuous-integration"},
+		},
+		RequiredPullRequestReviews: &RequiredPullRequestReviews{
+			IncludeAdmins: true,
 		},
 		Restrictions: &BranchRestrictions{
 			Users: []*User{