Add methods to update and delete milestones.

src/main/java/org/kohsuke/github/GHMilestone.java

@@ -85,10 +85,29 @@ public void reopen() throws IOException {
         edit("state", "open");
     }
 
+    /**
+     * Deletes this milestone.
+     */
+    public void delete() throws IOException {
+        root.retrieve().method("DELETE").to(getApiRoute());
+    }
+
     private void edit(String key, Object value) throws IOException {
         new Requester(root)._with(key, value).method("PATCH").to(getApiRoute());
     }
 
+    public void setTitle(String title) throws IOException {
+        edit("title", title);
+    }
+
+    public void setDescription(String description) throws IOException {
+        edit("description", description);
+    }
+
+    public void setDueOn(Date dueOn) throws IOException {
+        edit("due_on", GitHub.printDate(dueOn));
+    }
+
     protected String getApiRoute() {
         return "/repos/"+owner.getOwnerName()+"/"+owner.getName()+"/milestones/"+number;
     }

src/main/java/org/kohsuke/github/GitHub.java

@@ -956,7 +956,9 @@ public Reader renderMarkdown(String text) throws IOException {
     }
 
     /*package*/ static String printDate(Date dt) {
-        return new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'").format(dt);
+        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
+        df.setTimeZone(TimeZone.getTimeZone("GMT"));
+        return df.format(dt);
     }
 
     /*package*/ static final ObjectMapper MAPPER = new ObjectMapper();

src/test/java/org/kohsuke/github/GHMilestoneTest.java

@@ -0,0 +1,64 @@
+package org.kohsuke.github;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.util.Date;
+
+/**
+ * @author Martin van Zijl
+ */
+public class GHMilestoneTest extends AbstractGitHubWireMockTest {
+
+    @Before
+    @After
+    public void cleanUp() throws Exception {
+        // Cleanup is only needed when proxying
+        if (!mockGitHub.isUseProxy()) {
+            return;
+        }
+
+        for (GHMilestone milestone : getRepository(gitHubBeforeAfter).listMilestones(GHIssueState.ALL)) {
+            if ("Original Title".equals(milestone.getTitle()) ||
+                "Updated Title".equals(milestone.getTitle())) {
+                milestone.delete();
+            }
+        }
+    }
+
+    @Test
+    public void testUpdateMilestone() throws Exception {
+        GHRepository repo = getRepository();
+        GHMilestone milestone = repo.createMilestone("Original Title",
+                "To test the update methods");
+
+        String NEW_TITLE = "Updated Title";
+        String NEW_DESCRIPTION = "Updated Description";
+        Date NEW_DUE_DATE = GitHub.parseDate("2020-10-05T13:00:00Z");
+        Date OUTPUT_DUE_DATE = GitHub.parseDate("2020-10-05T07:00:00Z");
+
+        milestone.setTitle(NEW_TITLE);
+        milestone.setDescription(NEW_DESCRIPTION);
+        milestone.setDueOn(NEW_DUE_DATE);
+
+        // Force reload.
+        milestone = repo.getMilestone(milestone.getNumber());
+
+        assertEquals(NEW_TITLE, milestone.getTitle());
+        assertEquals(NEW_DESCRIPTION, milestone.getDescription());
+
+        // The time is truncated when sent to the server, but still part of the returned value
+        // 07:00 midnight PDT
+        assertEquals(OUTPUT_DUE_DATE, milestone.getDueOn());
+    }
+
+    protected GHRepository getRepository() throws IOException {
+        return getRepository(gitHub);
+    }
+
+    private GHRepository getRepository(GitHub gitHub) throws IOException {
+        return gitHub.getOrganization("github-api-test-org").getRepository("github-api");
+    }
+}

src/test/java/org/kohsuke/github/GitHubStaticTest.java

@@ -0,0 +1,72 @@
+package org.kohsuke.github;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.text.SimpleDateFormat;
+import java.time.Instant;
+import java.time.temporal.ChronoUnit;
+import java.util.Date;
+import java.util.TimeZone;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.not;
+
+/**
+ * Unit test for {@link GitHub} static helpers.
+ *
+ * @author Liam Newman
+ */
+public class GitHubStaticTest extends Assert {
+
+    @Test
+    public void timeRoundTrip() throws Exception {
+        Instant instantNow = Instant.now();
+
+        Date instantSeconds = Date.from(instantNow.truncatedTo(ChronoUnit.SECONDS));
+        Date instantMillis = Date.from(instantNow.truncatedTo(ChronoUnit.MILLIS));
+
+        // TODO: other formats
+        String instantFormatSlash = formatDate(instantMillis, "yyyy/MM/dd HH:mm:ss ZZZZ");
+        String instantFormatDash = formatDate(instantMillis, "yyyy-MM-dd'T'HH:mm:ss'Z'");
+        String instantFormatMillis = formatDate(instantMillis, "yyyy-MM-dd'T'HH:mm:ss.S'Z'");
+        String instantSecondsFormatMillis = formatDate(instantSeconds, "yyyy-MM-dd'T'HH:mm:ss.S'Z'");
+        String instantBadFormat = formatDate(instantMillis, "yy-MM-dd'T'HH:mm'Z'");
+
+
+        assertThat(GitHub.parseDate(GitHub.printDate(instantSeconds)),
+            equalTo(GitHub.parseDate(GitHub.printDate(instantMillis))));
+
+        assertThat(instantSeconds,
+            equalTo(GitHub.parseDate(GitHub.printDate(instantSeconds))));
+
+        assertThat(instantMillis,
+            not(equalTo(GitHub.parseDate(GitHub.printDate(instantMillis)))));
+
+        assertThat(instantSeconds,
+            equalTo(GitHub.parseDate(instantFormatSlash)));
+
+        assertThat(instantSeconds,
+            equalTo(GitHub.parseDate(instantFormatDash)));
+
+        assertThat(instantMillis,
+            equalTo(GitHub.parseDate(instantFormatMillis)));
+
+        assertThat(instantSeconds,
+            equalTo(GitHub.parseDate(instantSecondsFormatMillis)));
+
+        try {
+            GitHub.parseDate(instantBadFormat);
+            fail("Bad time format should throw.");
+        } catch (IllegalStateException e) {
+            assertThat(e.getMessage(), equalTo("Unable to parse the timestamp: " + instantBadFormat));
+        }
+    }
+
+    static String formatDate(Date dt, String format) {
+        SimpleDateFormat df = new SimpleDateFormat(format);
+        df.setTimeZone(TimeZone.getTimeZone("GMT"));
+        return df.format(dt);
+    }
+
+}

src/test/resources/org/kohsuke/github/GHMilestoneTest/wiremock/testUpdateMilestone/__files/orgs_github-api-test-org-fdbcaf38-478b-440a-851a-b5913757f6f3.json

@@ -0,0 +1,41 @@
+{
+  "login": "github-api-test-org",
+  "id": 7544739,
+  "node_id": "MDEyOk9yZ2FuaXphdGlvbjc1NDQ3Mzk=",
+  "url": "https://api.github.com/orgs/github-api-test-org",
+  "repos_url": "https://api.github.com/orgs/github-api-test-org/repos",
+  "events_url": "https://api.github.com/orgs/github-api-test-org/events",
+  "hooks_url": "https://api.github.com/orgs/github-api-test-org/hooks",
+  "issues_url": "https://api.github.com/orgs/github-api-test-org/issues",
+  "members_url": "https://api.github.com/orgs/github-api-test-org/members{/member}",
+  "public_members_url": "https://api.github.com/orgs/github-api-test-org/public_members{/member}",
+  "avatar_url": "https://avatars3.githubusercontent.com/u/7544739?v=4",
+  "description": null,
+  "is_verified": false,
+  "has_organization_projects": true,
+  "has_repository_projects": true,
+  "public_repos": 10,
+  "public_gists": 0,
+  "followers": 0,
+  "following": 0,
+  "html_url": "https://github.com/github-api-test-org",
+  "created_at": "2014-05-10T19:39:11Z",
+  "updated_at": "2015-04-20T00:42:30Z",
+  "type": "Organization",
+  "total_private_repos": 0,
+  "owned_private_repos": 0,
+  "private_gists": 0,
+  "disk_usage": 132,
+  "collaborators": 0,
+  "billing_email": "[email protected]",
+  "default_repository_permission": "none",
+  "members_can_create_repositories": false,
+  "two_factor_requirement_enabled": false,
+  "plan": {
+    "name": "free",
+    "space": 976562499,
+    "private_repos": 0,
+    "filled_seats": 7,
+    "seats": 0
+  }
+}