diff --git a/examples/tests/d/aiken.toml b/examples/tests/d/aiken.toml
new file mode 100644
index 00000000..762f80f1
--- /dev/null
+++ b/examples/tests/d/aiken.toml
@@ -0,0 +1,2 @@
+name = "test_d"
+version = "0.0.0"
diff --git a/examples/tests/d/lib/main.ak b/examples/tests/d/lib/main.ak
new file mode 100644
index 00000000..f9359d1a
--- /dev/null
+++ b/examples/tests/d/lib/main.ak
@@ -0,0 +1,18 @@
+pub fn foldr(xs: List(a), f: fn(a, b) -> b, zero: b) -> b {
+  when xs is {
+    [] -> zero
+    [x, ..rest] -> f(x, foldr(rest, f, zero))
+  }
+}
+
+pub fn prepend(x: a, xs: List(a)) -> List(a) {
+  [x, ..xs]
+}
+
+pub fn concat(left: List(a), right: List(a)) -> List(a) {
+  foldr(left, prepend, right)
+}
+
+test concat_1() {
+  concat([1, 2, 3], [4, 5, 6]) == [1, 2, 3, 4, 5, 6]
+}