diff --git a/src/test/java/com/github/underscore/LodashTest.java b/src/test/java/com/github/underscore/LodashTest.java
index 837f0377..7a47cb4c 100644
--- a/src/test/java/com/github/underscore/LodashTest.java
+++ b/src/test/java/com/github/underscore/LodashTest.java
@@ -413,8 +413,7 @@ void set() {
                 U.<String>set(
                                 (Map<String, Object>) U.fromJson("{\"a\":[{\"b\":{\"c\":\"d\"}}]}"),
                                 "a[0].b.c",
-                                "e")
-                        .toString());
+                                "e"));
         assertEquals(
                 "{b={c=d}}",
                 U.set(
@@ -428,7 +427,7 @@ void set() {
         map.put("a", map2);
         map2.put("#item", map3);
         map3.put("b", "c");
-        assertEquals("c", U.<String>set(map, "a.b", "b").toString());
+        assertEquals("c", U.<String>set(map, "a.b", "b"));
         assertNull(U.<String>set((Map<String, Object>) null, "a", "b"));
         assertNull(U.<String>set(new LinkedHashMap<String, Object>(), "a.b", "b"));
         Map<String, Object> map4 = new LinkedHashMap<>();
diff --git a/src/test/java/com/github/underscore/ObjectsTest.java b/src/test/java/com/github/underscore/ObjectsTest.java
index 69f380c3..9cc8174f 100644
--- a/src/test/java/com/github/underscore/ObjectsTest.java
+++ b/src/test/java/com/github/underscore/ObjectsTest.java
@@ -174,7 +174,7 @@ void pick() {
                                 put("userid", "moe1");
                             }
                         },
-                        value -> value instanceof Number);
+                        Number.class::isInstance);
         assertEquals("[age=50]", result2.toString());
     }
 
@@ -208,7 +208,7 @@ void omit() {
                                 put("userid", "moe1");
                             }
                         },
-                        value -> value instanceof Number);
+                        Number.class::isInstance);
         assertEquals("[name=moe, userid=moe1]", result2.toString());
     }
 
diff --git a/src/test/java/com/github/underscore/UnderscoreTest.java b/src/test/java/com/github/underscore/UnderscoreTest.java
index c3bc1f83..2d8b32a5 100644
--- a/src/test/java/com/github/underscore/UnderscoreTest.java
+++ b/src/test/java/com/github/underscore/UnderscoreTest.java
@@ -166,9 +166,9 @@ void push() {
     @SuppressWarnings("unchecked")
     @Test
     void pop() {
-        assertEquals("c", Underscore.pop(asList("a", "b", "c")).getKey().toString());
+        assertEquals("c", Underscore.pop(asList("a", "b", "c")).getKey());
         assertEquals("c", new Underscore(asList("a", "b", "c")).pop().getKey().toString());
-        assertEquals("c", Underscore.chain(asList("a", "b", "c")).pop().item().getKey().toString());
+        assertEquals("c", Underscore.chain(asList("a", "b", "c")).pop().item().getKey());
     }
 
     /*
@@ -178,7 +178,7 @@ void pop() {
     @SuppressWarnings("unchecked")
     @Test
     void shift() {
-        assertEquals("a", Underscore.shift(asList("a", "b", "c")).getKey().toString());
+        assertEquals("a", Underscore.shift(asList("a", "b", "c")).getKey());
         assertEquals("a", new Underscore(asList("a", "b", "c")).shift().getKey().toString());
         assertEquals(
                 "a", Underscore.chain(asList("a", "b", "c")).shift().item().getKey().toString());
@@ -541,7 +541,7 @@ void optional() {
         assertEquals("1", Optional.of(1).orElse(null).toString());
         assertFalse(Optional.<Integer>empty().map(arg -> "" + arg).isPresent());
         assertTrue(Optional.<Integer>empty().map(arg -> "" + arg).isEmpty());
-        assertEquals("1", Optional.of(1).map(arg -> "" + arg).get().toString());
+        assertEquals("1", Optional.of(1).map(arg -> "" + arg).get());
         try {
             Optional.empty().get();
             fail("IllegalStateException expected");