feat(#1237): Verify pull request check runs before merging changes

pom.xml

@@ -291,7 +291,7 @@ OF THE POSSIBILITY OF SUCH DAMAGE.
     <dependency>
       <groupId>com.jcabi</groupId>
       <artifactId>jcabi-github</artifactId>
-      <version>1.4.2</version>
+      <version>2.0-SNAPSHOT</version>
     </dependency>
     <dependency>
       <groupId>com.jcabi</groupId>

src/main/java/com/rultor/agents/github/qtn/QnMerge.java

@@ -30,6 +30,7 @@
 package com.rultor.agents.github.qtn;
 
 import com.jcabi.aspects.Immutable;
+import com.jcabi.github.Check;
 import com.jcabi.github.Comment;
 import com.jcabi.github.Issue;
 import com.jcabi.github.Pull;
@@ -40,6 +41,7 @@
 import com.rultor.agents.github.Req;
 import java.io.IOException;
 import java.net.URI;
+import java.util.Collection;
 import java.util.ResourceBundle;
 import lombok.EqualsAndHashCode;
 import lombok.ToString;
@@ -72,21 +74,29 @@ public Req understand(final Comment.Smart comment,
         final Issue.Smart issue = new Issue.Smart(comment.issue());
         final Req req;
         if (issue.isPull() && issue.isOpen()) {
-            new Answer(comment).post(
-                true,
-                String.format(
-                    QnMerge.PHRASES.getString("QnMerge.start"),
-                    home.toASCIIString()
-                )
-            );
             Logger.info(
                 this, "merge request found in %s#%d, comment #%d",
                 issue.repo().coordinates(), issue.number(), comment.number()
             );
-            req = QnMerge.pack(
-                comment,
-                issue.repo().pulls().get(issue.number())
-            );
+            if (QnMerge.allChecksSuccessful(issue.pull())) {
+                new Answer(comment).post(
+                    true,
+                    String.format(
+                        QnMerge.PHRASES.getString("QnMerge.start"),
+                        home.toASCIIString()
+                    )
+                );
+                req = QnMerge.pack(
+                    comment,
+                    issue.repo().pulls().get(issue.number())
+                );
+            } else {
+                new Answer(comment).post(
+                    false,
+                    QnMerge.PHRASES.getString("QnMerge.checks-are-failed")
+                );
+                req = Req.EMPTY;
+            }
         } else {
             new Answer(comment).post(
                 false,
@@ -164,4 +174,21 @@ private static Req pack(final Comment.Smart comment,
         return req;
     }
 
+    /**
+     * Checks if all checks are successful.
+     * @param pull Pull
+     * @return True if all checks are successful
+     * @throws IOException If fails
+     */
+    private static boolean allChecksSuccessful(final Pull pull) throws IOException {
+        boolean result = true;
+        for (final Check check : pull.checks().all()) {
+            if (!check.successful()) {
+                result = false;
+                break;
+            }
+        }
+        return result;
+    }
+
 }

src/test/java/com/rultor/agents/github/qtn/QnMergeTest.java

@@ -29,10 +29,14 @@
  */
 package com.rultor.agents.github.qtn;
 
+import com.jcabi.github.Check;
+import com.jcabi.github.Checks;
 import com.jcabi.github.Comment;
 import com.jcabi.github.Comments;
+import com.jcabi.github.Pull;
 import com.jcabi.github.Repo;
 import com.jcabi.github.mock.MkBranches;
+import com.jcabi.github.mock.MkChecks;
 import com.jcabi.github.mock.MkGithub;
 import com.jcabi.matchers.XhtmlMatchers;
 import com.rultor.agents.github.Req;
@@ -45,6 +49,7 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
 import org.xembly.Directives;
 import org.xembly.Xembler;
 
@@ -74,6 +79,7 @@ final class QnMergeTest {
      * All pull request comments.
      */
     private transient Comments comments;
+    private Pull pull;
 
     /**
      * Initial phase for all tests.
@@ -87,8 +93,9 @@ public void setUp() throws IOException {
         final String base = "base";
         branches.create(head, "abcdef4");
         branches.create(base, "abcdef5");
+        pull = repo.pulls().create("", head, base);
         this.comments = repo.issues()
-            .get(repo.pulls().create("", head, base).number())
+            .get(pull.number())
             .comments();
     }
 
@@ -98,7 +105,7 @@ public void setUp() throws IOException {
      */
     @Test
     public void buildsRequest() throws Exception {
-        final String request = new Xembler(this.requestDirectives()).xml();
+        final String request = new Xembler(this.mergeRequest()).xml();
         MatcherAssert.assertThat(
             request,
             Matchers.allOf(
@@ -130,36 +137,48 @@ public void buildsRequest() throws Exception {
      * QnMerge can not build a request because some GitHub checks
      *  were failed.
      * @throws Exception In case of error
-     * @todo #1237:90min We need to implement a verification logic
-     *  for GitHub checks to determine whether they were completed
-     *  correctly or not. If not, Rultor should not create a merge
-     *  request and must display a comment to the user. Once the logic
-     *  is implemented, we can enable that test.
      */
     @Test
-    @Disabled
     public void stopsBecauseCiChecksFailed() throws Exception {
-        final String request = new Xembler(this.requestDirectives()).xml();
+        final MkChecks checks = (MkChecks) this.pull.checks();
+        checks.create(Check.Status.IN_PROGRESS, Check.Conclusion.SUCCESS);
+        this.mergeRequest();
         MatcherAssert.assertThat(
             new Comment.Smart(this.comments.get(1)).body(),
             Matchers.is(QnMergeTest.COMMAND)
         );
         MatcherAssert.assertThat(
             new Comment.Smart(this.comments.get(2)).body(),
-            Matchers.equalTo(
+            Matchers.containsString(
                 QnMergeTest.PHRASES.getString("QnMerge.checks-are-failed")
             )
         );
-        MatcherAssert.assertThat(request, Matchers.equalTo(Req.EMPTY));
+    }
+
+    @Test
+    public void continuesBecauseCiChecksSuccessful() throws Exception {
+        final MkChecks checks = (MkChecks) this.pull.checks();
+        checks.create(Check.Status.COMPLETED, Check.Conclusion.SUCCESS);
+        this.mergeRequest();
+        MatcherAssert.assertThat(
+            new Comment.Smart(this.comments.get(1)).body(),
+            Matchers.is(QnMergeTest.COMMAND)
+        );
+        MatcherAssert.assertThat(
+            new Comment.Smart(this.comments.get(2)).body(),
+            Matchers.containsString(
+                String.format(QnMergeTest.PHRASES.getString("QnMerge.start"), "#")
+            )
+        );
     }
 
     /**
-     * Request directives.
+     * Merge request directives.
      * @return Directives
      * @throws IOException In case of error
      * @throws URISyntaxException In case of error
      */
-    private Directives requestDirectives() throws IOException,
+    private Directives mergeRequest() throws IOException,
         URISyntaxException {
         return new Directives()
             .add("request")