Add delete_ref in RepoHandler (#573)

Fixes: #572

src/api/repos.rs

@@ -210,6 +210,32 @@ impl<'octo> RepoHandler<'octo> {
             .await
     }
 
+    /// Deletes an existing reference from the repository.
+    /// ```no_run
+    /// # async fn run() -> octocrab::Result<()> {
+    /// # let master_sha = "";
+    /// use octocrab::params::repos::Reference;
+    ///
+    /// // Deletes the "heads/temporary-branch" reference.
+    /// octocrab::instance()
+    ///     .repos("owner", "repo")
+    ///     .delete_ref(&Reference::Branch("temporary-branch".to_string()))
+    ///     .await?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub async fn delete_ref(&self, reference: &params::repos::Reference) -> Result<()> {
+        let route = format!(
+            "/repos/{owner}/{repo}/git/refs/{ref}",
+            owner = self.owner,
+            repo = self.repo,
+            ref = reference.ref_url()
+        );
+        crate::map_github_error(self.crab._delete(route, None::<&()>).await?)
+            .await
+            .map(drop)
+    }
+
     /// Get repository content.
     /// ```no_run
     /// # async fn run() -> octocrab::Result<()> {

tests/repo_delete_ref_test.rs

@@ -0,0 +1,56 @@
+mod mock_error;
+
+use mock_error::setup_error_handler;
+use octocrab::{params::repos::Reference, Octocrab};
+use wiremock::{
+    matchers::{method, path},
+    Mock, MockServer, ResponseTemplate,
+};
+
+async fn setup_delete_ref_api(template: ResponseTemplate) -> MockServer {
+    let owner: &str = "org";
+    let repo: &str = "some-repo";
+    let reference: &str = "heads/foo";
+
+    let mock_server = MockServer::start().await;
+
+    Mock::given(method("DELETE"))
+        .and(path(format!("/repos/{owner}/{repo}/git/refs/{reference}")))
+        .respond_with(template.clone())
+        .mount(&mock_server)
+        .await;
+
+    setup_error_handler(
+        &mock_server,
+        &format!("DELETE on /repos/{owner}/{repo}/git/refs/{reference} was not received"),
+    )
+    .await;
+    mock_server
+}
+
+fn setup_octocrab(uri: &str) -> Octocrab {
+    Octocrab::builder().base_uri(uri).unwrap().build().unwrap()
+}
+
+const OWNER: &str = "org";
+const REPO: &str = "some-repo";
+const BRANCH: &str = "foo";
+
+#[tokio::test]
+async fn should_delete_reference() {
+    let template = ResponseTemplate::new(204);
+    let mock_server = setup_delete_ref_api(template).await;
+    let client = setup_octocrab(&mock_server.uri());
+
+    let repos = client.repos(OWNER.to_owned(), REPO.to_owned());
+
+    let result = repos
+        .delete_ref(&Reference::Branch(BRANCH.to_owned()))
+        .await;
+
+    assert!(
+        result.is_ok(),
+        "expected successful result, got error: {:#?}",
+        result
+    );
+}