Added hashmap tests

ts-rs/tests/hashmap.rs

@@ -0,0 +1,37 @@
+use std::collections::{HashMap, HashSet};
+use ts_rs::TS;
+
+#[test]
+fn hashmap() {
+    #[derive(TS)]
+    #[allow(dead_code)]
+    struct Hashes {
+        map: HashMap<String, String>,
+        set: HashSet<String>,
+    }
+
+    assert_eq!(
+        Hashes::decl(),
+        "interface Hashes { map: Record<string, string>, set: Array<string>, }"
+    )
+}
+
+#[test]
+fn hashmap_with_custom_hasher() {
+    struct CustomHasher {}
+
+    type CustomHashMap<K, V> = HashMap<K, V, CustomHasher>;
+    type CustomHashSet<K> = HashSet<K, CustomHasher>;
+
+    #[derive(TS)]
+    #[allow(dead_code)]
+    struct Hashes {
+        map: CustomHashMap<String, String>,
+        set: CustomHashSet<String>,
+    }
+
+    assert_eq!(
+        Hashes::decl(),
+        "interface Hashes { map: Record<string, string>, set: Array<string>, }"
+    )
+}