diff --git a/tools/canoninja/canoninja_test.go b/tools/canoninja/canoninja_test.go
new file mode 100644
index 0000000..3c45f8c
--- /dev/null
+++ b/tools/canoninja/canoninja_test.go
@@ -0,0 +1,47 @@
+package canoninja
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestGenerate(t *testing.T) {
+	tests := []struct {
+		name     string
+		in       []byte
+		wantSink string
+		wantErr  bool
+	}{
+		{
+			name: "1",
+			in: []byte(`
+rule rule1
+  abcd
+rule rule2
+  abcd
+build x: rule1
+`),
+			wantSink: `
+rule R9c97aba7f61994be6862f5ea9a62d26130c7f48b
+  abcd
+rule R9c97aba7f61994be6862f5ea9a62d26130c7f48b
+  abcd
+build x: R9c97aba7f61994be6862f5ea9a62d26130c7f48b
+`,
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			sink := &bytes.Buffer{}
+			err := Generate("<file>", tt.in, sink)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("Generate() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if gotSink := sink.String(); gotSink != tt.wantSink {
+				t.Errorf("Generate() gotSink = %v, want %v", gotSink, tt.wantSink)
+			}
+		})
+	}
+}