diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 2875c7b..658ab2c 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -1,4 +1,7 @@
-on: [push, pull_request]
+on:
+  push:
+    branches: [ main ]
+  pull_request:
 
 name: Continuous integration
 
@@ -62,3 +65,17 @@ jobs:
         with:
           command: clippy
           args: -- -D warnings
+
+  coverage:
+    name: Code Coverage
+    runs-on: ubuntu-latest
+    env:
+      CARGO_TERM_COLOR: always
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Rust
+        run: rustup update stable
+      - name: Install cargo-llvm-cov
+        uses: taiki-e/install-action@cargo-llvm-cov
+      - name: Generate code coverage
+        run: cargo llvm-cov -p todolist --fail-uncovered-lines 0
diff --git a/domain/todolist/src/lib.rs b/domain/todolist/src/lib.rs
index 9256bd4..db02a72 100644
--- a/domain/todolist/src/lib.rs
+++ b/domain/todolist/src/lib.rs
@@ -19,7 +19,7 @@ pub enum Command {
 #[derive(Debug)]
 pub enum Error {}
 
-#[derive(Serialize, Deserialize)]
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
 pub enum Event {
     TaskAdded { description: String },
     TaskCompleted { index: usize },
diff --git a/sort_derive.py b/sort_derive.py
new file mode 100644
index 0000000..e55f1e8
--- /dev/null
+++ b/sort_derive.py
@@ -0,0 +1,41 @@
+import os
+import fileinput
+import re
+
+a = re.compile(r"^#\[derive\((\s*[a-zA-Z0-9_]+\s*,)*(\s*[a-zA-Z0-9_]+\s*)\)]$")
+
+special = [
+    "Copy",
+    "Clone",
+    "Default",
+    "Debug",
+    "PartialEq",
+    "Eq",
+    "PartialOrd",
+    "Ord",
+    "Serialize",
+    "Deserialize",
+]
+
+special = {x: i for i, x in enumerate(special)}
+
+for root, dirs, files in os.walk("."):
+    if "target" in root:
+        continue
+    for name in files:
+        path = root + os.sep + name
+
+        if name.endswith(".rs"):
+            print(path)
+            for line in fileinput.input(path, inplace=True):
+                if a.match(line):
+                    derives = line[9:-3]
+                    derives = [
+                        (special.get(x.strip(), 100), x.strip())
+                        for x in derives.split(",")
+                    ]
+                    derives.sort()
+                    line = "#[derive(" + ", ".join(x[1] for x in derives) + ")]"
+                    print(line)
+                else:
+                    print(line, end="")