diff --git a/.gitignore b/.gitignore
index e94e32b..82bfc13 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 *.tgz
+coverage/
 node_modules/
diff --git a/src/GitHubClient.js b/src/GitHubClient.js
index ac0af2a..5cc9cbd 100644
--- a/src/GitHubClient.js
+++ b/src/GitHubClient.js
@@ -83,13 +83,24 @@ function makeReview(diff, makeClient = makeGitHubClient) {
   const parse = require("parse-diff");
   const files = parse(diff);
   if (files.length <= 0) {
-    return process.exit(0);
+    return Promise.resolve();
   }
 
-  const { GITHUB_REPOSITORY, GITHUB_TOKEN } = process.env;
-
-  const octokit = makeClient({ auth: GITHUB_TOKEN });
+  const comments = files.reduce((comments, file) => {
+    const { chunks, to } = file;
+    if (chunks.length === 0) {
+      return comments;
+    }
+    return chunks.reduce((comments, chunk) => {
+      comments.push(makeComment(to, chunk));
+      return comments;
+    }, comments);
+  }, []);
+  if (comments.length === 0) {
+    return Promise.resolve();
+  }
 
+  const { GITHUB_REPOSITORY, GITHUB_TOKEN } = process.env;
   const [owner, repo] = GITHUB_REPOSITORY.split("/");
   const review = {
     accept: "application/vnd.github.comfort-fade-preview+json",
@@ -97,19 +108,15 @@ function makeReview(diff, makeClient = makeGitHubClient) {
     repo,
     pull_number: makeClient === makeGitHubClient ? getPullRequestNumber() : 0,
     event: "COMMENT",
-    comments: files.reduce((comments, file) => {
-      const { chunks, to } = file;
-      return chunks.reduce((comments, chunk) => {
-        comments.push(makeComment(to, chunk));
-        return comments;
-      }, comments);
-    }, []),
+    comments,
   };
-  octokit.pulls.createReview(review).catch((e) => {
-    console.error(e);
-    console.dir(review, undefined, { depth: null });
-    return process.exit(1);
-  });
+  return makeClient({ auth: GITHUB_TOKEN })
+    .pulls.createReview(review)
+    .catch((e) => {
+      console.error(e);
+      console.dir(review, undefined, { depth: null });
+      return process.exit(1);
+    });
 }
 
 module.exports = {
diff --git a/tests/suggest.test.js b/tests/suggest.test.js
index 708422e..9c0688e 100644
--- a/tests/suggest.test.js
+++ b/tests/suggest.test.js
@@ -34,6 +34,23 @@ describe("suggest", () => {
     env.GITHUB_REPOSITORY = env.GITHUB_REPOSITORY || "tido64/suggestion-bot";
   });
 
+  test("skips invalid diffs", async () => {
+    let payload = undefined;
+    const createReview = (review) => {
+      payload = review;
+      return Promise.resolve();
+    };
+
+    await makeReview("", makeMockClient(createReview));
+    expect(payload).toBeUndefined();
+
+    await makeReview(
+      "diff --git a/src/Graphics/TextureAllocator.gl.h b/src/Graphics/TextureAllocator.gl.h",
+      makeMockClient(createReview)
+    );
+    expect(payload).toBeUndefined();
+  });
+
   test("supports unified diffs", async () => {
     let payload = undefined;
     await makeReview(