diff --git a/Makefile b/Makefile
index 7bae6f4..aa9a517 100644
--- a/Makefile
+++ b/Makefile
@@ -1,16 +1,15 @@
-all: update lint fmt test
+all: lint fmt test
 
 update:
 	go get -u ./...
 	go mod tidy
 
 lint:
+	go vet ./...
 	golangci-lint run
 
 fmt:
-	go install mvdan.cc/gofumpt@latest
 	go fmt ./...
-	gofumpt -w .
 
 test:
 	go test -v ./...
diff --git a/main.go b/main.go
index 2d1e643..2cb56bb 100644
--- a/main.go
+++ b/main.go
@@ -17,13 +17,13 @@ const (
 )
 
 func main() {
-	if err := run(os.Args, os.Stdin, os.Stdout); err != nil {
+	if err := run(os.Args, os.Stdout, os.Stderr); err != nil {
 		_, _ = fmt.Fprintf(os.Stderr, "%v\n", err)
 		os.Exit(exitFail)
 	}
 }
 
-func run(args []string, _ io.Reader, stdout io.Writer) error {
+func run(args []string, stdout io.Writer, stderr io.Writer) error {
 	// get all directories passed as arguments and put them in a slice
 	directories := getDirectoriesFromArgs(args)
 	log(stdout, "Passed Directories:", directories)
@@ -32,7 +32,7 @@ func run(args []string, _ io.Reader, stdout io.Writer) error {
 	for _, directory := range directories {
 		allFiles, err := getFilesRecursive(directory, fileExtension)
 		if err != nil {
-			log(stdout, err)
+			log(stderr, err)
 			continue
 		}
 
@@ -49,7 +49,7 @@ func run(args []string, _ io.Reader, stdout io.Writer) error {
 				if ziptools.IsValidZip(file) {
 					log(stdout, ".")
 				} else {
-					log(stdout, "Invalid zip file:", file)
+					log(stderr, "Invalid zip file:", file)
 				}
 				<-semaphore
 			}(file)
diff --git a/main_test.go b/main_test.go
index 826d5c7..d5f8020 100644
--- a/main_test.go
+++ b/main_test.go
@@ -17,28 +17,24 @@ func testfile(name string) string {
 
 func TestRun(t *testing.T) {
 	type args struct {
-		stdin string
-		args  []string
+		args []string
 	}
 
 	tests := []struct {
 		name       string
 		args       args
 		wantStdout string
+		wantStderr string
 		wantErr    bool
 	}{
-		{"no args no stdin", args{"empty", []string{"zipcheck", ""}}, "emptyStdout", false},
-		{"fake directory", args{"empty", []string{"zipcheck", "aaaaaaa"}}, "fakeStdout", false},
-		{"good directory", args{"empty", []string{"zipcheck", "testdata"}}, "goodStdout", false},
+		{"no args no stdin", args{[]string{"zipcheck", ""}}, "emptyStdout", "emptyStderr", false},
+		{"fake directory", args{[]string{"zipcheck", "aaaaaaa"}}, "fakeStdout", "fakeStderr", false},
+		{"good directory", args{[]string{"zipcheck", "testdata"}}, "goodStdout", "goodStderr", false},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			stdout := &bytes.Buffer{}
-			stdinB, err := os.ReadFile(testfile(tt.args.stdin))
-			if err != nil {
-				t.Errorf("Failed reading test file %s: %v", tt.args.stdin, err)
-			}
-			stdin := bytes.NewReader(stdinB)
+			stderr := &bytes.Buffer{}
 
 			wantStdoutB, err := os.ReadFile(testfile(tt.wantStdout))
 			if err != nil {
@@ -46,7 +42,13 @@ func TestRun(t *testing.T) {
 			}
 			wantStdout := string(wantStdoutB)
 
-			err = run(tt.args.args, stdin, stdout)
+			wantStderrB, err := os.ReadFile(testfile(tt.wantStderr))
+			if err != nil {
+				t.Errorf("Failed reading test file %s: %v", tt.wantStderr, err)
+			}
+			wantStderr := string(wantStderrB)
+
+			err = run(tt.args.args, stdout, stderr)
 			if (err != nil) != tt.wantErr {
 				t.Errorf("run() error = %v, wantErr %v", err, tt.wantErr)
 				return
@@ -54,6 +56,9 @@ func TestRun(t *testing.T) {
 			if gotStdout := stdout.String(); gotStdout != wantStdout {
 				t.Errorf("run() gotStdout = %v, want %v", gotStdout, wantStdout)
 			}
+			if gotStderr := stderr.String(); gotStderr != wantStderr {
+				t.Errorf("run() gotStderr = %v, want %v", gotStderr, wantStderr)
+			}
 		})
 	}
 }
diff --git a/testdata/emptyStderr b/testdata/emptyStderr
new file mode 100644
index 0000000..97d7d95
--- /dev/null
+++ b/testdata/emptyStderr
@@ -0,0 +1 @@
+directory  does not exist
diff --git a/testdata/emptyStdout b/testdata/emptyStdout
index 7b6e7d1..c0cf2ab 100644
--- a/testdata/emptyStdout
+++ b/testdata/emptyStdout
@@ -1,2 +1 @@
 Passed Directories: []
-directory  does not exist
diff --git a/testdata/fakeStderr b/testdata/fakeStderr
new file mode 100644
index 0000000..0616309
--- /dev/null
+++ b/testdata/fakeStderr
@@ -0,0 +1 @@
+directory aaaaaaa does not exist
diff --git a/testdata/fakeStdout b/testdata/fakeStdout
index 505e3b5..1b8c3e1 100644
--- a/testdata/fakeStdout
+++ b/testdata/fakeStdout
@@ -1,2 +1 @@
 Passed Directories: [aaaaaaa]
-directory aaaaaaa does not exist
diff --git a/testdata/goodStderr b/testdata/goodStderr
new file mode 100644
index 0000000..e5d1a33
--- /dev/null
+++ b/testdata/goodStderr
@@ -0,0 +1,2 @@
+Invalid zip file: testdata/incomplete.zip
+Invalid zip file: testdata/bad_01.zip
diff --git a/testdata/goodStdout b/testdata/goodStdout
index e80c7cd..abb6445 100644
--- a/testdata/goodStdout
+++ b/testdata/goodStdout
@@ -1,5 +1,3 @@
 Passed Directories: [testdata]
 Found 3 zip files in: testdata
-Invalid zip file: testdata/incomplete.zip
 .
-Invalid zip file: testdata/bad_01.zip