diff --git a/src/flamegraph/color/palettes.rs b/src/flamegraph/color/palettes.rs
index c172e325..750e8e3f 100644
--- a/src/flamegraph/color/palettes.rs
+++ b/src/flamegraph/color/palettes.rs
@@ -100,3 +100,33 @@ pub(super) mod wakeup {
         BasicPalette::Aqua
     }
 }
+
+#[cfg(test)]
+mod tests {
+
+    struct TestData {
+        input: String,
+        output: BasicPalette
+    }
+
+    #[test]
+    fn js_returns_correct() {
+        use super::js;
+        use crate::flamegraph::color::BasicPalette;
+
+        let test_data = [
+            TestData {input: String::from(" "), output: BasicPalette::Green}, 
+            TestData {input: String::from("something_[k]"), output: BasicPalette::Orange},
+            TestData {input: String::from("something/_[j]"), output: BasicPalette::Green},
+            TestData {input: String::from("something_[j]"), output: BasicPalette::Aqua},
+            TestData {input: String::from("some::thing"), output: BasicPalette::Yellow},
+            TestData {input: String::from("some:thing"), output: BasicPalette::Aqua},
+            TestData {input: String::from("some/ai.js"), output: BasicPalette::Green},
+            TestData {input: String::from("someai.js"), output: BasicPalette::Red},
+        ];
+        for elem in test_data.iter() {
+            let result = js::resolve(&elem.input);
+            assert_eq!(result, elem.output);
+        }
+    }
+}