diff --git a/function/function_test.go b/function/function_test.go
new file mode 100644
index 0000000..7c942ca
--- /dev/null
+++ b/function/function_test.go
@@ -0,0 +1,44 @@
+package function_test
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"tangled.org/cosmeak.tngl.sh/weave"
+	"tangled.org/cosmeak.tngl.sh/weave/function"
+)
+
+func TestFunctionGeneration(t *testing.T) {
+	out := t.TempDir()
+
+	pack := weave.
+		MkDatapack("test", "Test pack", 88, 88, []string{"vanilla"}).
+		AddFeature(function.MkFunction(
+			"set_day",
+			"time set day",
+			"say Daytime!",
+		))
+
+	if err := pack.Generate(out); err != nil {
+		t.Fatalf("generate failed: %v", err)
+	}
+
+	path := filepath.Join(
+		out,
+		"test", "data", "test", "function", "set_day.mcfunction",
+	)
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("expected file not found: %v", err)
+	}
+
+	got := strings.TrimSpace(string(data))
+	want := "time set day\nsay Daytime!"
+
+	if got != want {
+		t.Errorf("unexpected file content:\n%s", got)
+	}
+}