chore: add more tests (#3338)

core/proc/goroutines_test.go

@@ -1,6 +1,10 @@
+//go:build linux || darwin
+
 package proc
 
 import (
+	"errors"
+	"os"
 	"strings"
 	"testing"
 
@@ -9,7 +13,29 @@ import (
 )
 
 func TestDumpGoroutines(t *testing.T) {
-	buf := logtest.NewCollector(t)
-	dumpGoroutines()
-	assert.True(t, strings.Contains(buf.String(), ".dump"))
+	t.Run("real file", func(t *testing.T) {
+		buf := logtest.NewCollector(t)
+		dumpGoroutines(fileCreator{})
+		assert.True(t, strings.Contains(buf.String(), ".dump"))
+	})
+
+	t.Run("fake file", func(t *testing.T) {
+		const msg = "any message"
+		buf := logtest.NewCollector(t)
+		err := errors.New(msg)
+		dumpGoroutines(fakeCreator{
+			file: &os.File{},
+			err:  err,
+		})
+		assert.True(t, strings.Contains(buf.String(), msg))
+	})
+}
+
+type fakeCreator struct {
+	file *os.File
+	err  error
+}
+
+func (fc fakeCreator) Create(name string) (file *os.File, err error) {
+	return fc.file, fc.err
 }