diff --git a/.golangci.yml b/.golangci.yml
index c5a183c..3669242 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -12,7 +12,6 @@ linters:
     # These are all considered deprecated: https://github.com/golangci/golangci-lint/issues/1841
     - deadcode
     - structcheck
-    - unused
     - varcheck
 linters-settings:
   exhaustive:
diff --git a/fail.go b/fail.go
new file mode 100644
index 0000000..bb37bf6
--- /dev/null
+++ b/fail.go
@@ -0,0 +1,17 @@
+package wsrpc
+
+import (
+	"errors"
+	"os"
+	"testing"
+)
+
+func FailLintOutOfTestFile(t *testing.T) {
+	const UnusedVar = 1 // lint should complain for unused variable
+	const ALL_CAPS = 10 // should be camel cased
+	err := os.ErrNotExist
+	if err == os.ErrNotExist { // should use errors.Is
+		err := errors.New("fake error") // shadowed variable
+		t.Log(err)
+	}
+}
diff --git a/fail_test.go b/fail_test.go
new file mode 100644
index 0000000..211e42c
--- /dev/null
+++ b/fail_test.go
@@ -0,0 +1,39 @@
+package wsrpc
+
+import (
+	"errors"
+	"os"
+	"sync"
+	"testing"
+)
+
+// func TestFail(t *testing.T) {
+// 	if testing.Short() {
+// 		t.Skip()
+// 	}
+// 	t.Fatal("fake failure")
+// }
+
+func TestRace(t *testing.T) {
+	var v int
+	var wg sync.WaitGroup
+	wg.Add(100)
+	for i := 0; i < 100; i++ {
+		go func() {
+			defer wg.Done()
+			v++
+			v--
+		}()
+	}
+	wg.Wait()
+	t.Log(v)
+}
+
+func TestLint(t *testing.T) {
+	const ALL_CAPS = 10 // should be AllCaps
+	err := os.ErrNotExist
+	if err == os.ErrNotExist { // should use errors.Is
+		err := errors.New("fake error") // shadowed variable
+		t.Log(err)
+	}
+}