diff --git a/cmd/prometheus/main_test.go b/cmd/prometheus/main_test.go
index 532ee5d271..0d0ab56eb4 100644
--- a/cmd/prometheus/main_test.go
+++ b/cmd/prometheus/main_test.go
@@ -252,6 +252,8 @@ func TestWALSegmentSizeBounds(t *testing.T) {
 			// WaitGroup is used to ensure that we don't call t.Log() after the test has finished.
 			var wg sync.WaitGroup
 			wg.Add(1)
+			defer wg.Wait()
+
 			go func() {
 				defer wg.Done()
 				slurp, _ := io.ReadAll(stderr)
@@ -271,7 +273,6 @@ func TestWALSegmentSizeBounds(t *testing.T) {
 					prom.Process.Kill()
 					<-done
 				}
-				wg.Wait()
 				return
 			}
 
@@ -281,8 +282,6 @@ func TestWALSegmentSizeBounds(t *testing.T) {
 			require.ErrorAs(t, err, &exitError)
 			status := exitError.Sys().(syscall.WaitStatus)
 			require.Equal(t, tc.exitCode, status.ExitStatus())
-
-			wg.Wait()
 		})
 	}
 }
@@ -313,7 +312,14 @@ func TestMaxBlockChunkSegmentSizeBounds(t *testing.T) {
 			// Log stderr in case of failure.
 			stderr, err := prom.StderrPipe()
 			require.NoError(t, err)
+
+			// WaitGroup is used to ensure that we don't call t.Log() after the test has finished.
+			var wg sync.WaitGroup
+			wg.Add(1)
+			defer wg.Wait()
+
 			go func() {
+				defer wg.Done()
 				slurp, _ := io.ReadAll(stderr)
 				t.Log(string(slurp))
 			}()
@@ -511,6 +517,8 @@ func TestModeSpecificFlags(t *testing.T) {
 			// WaitGroup is used to ensure that we don't call t.Log() after the test has finished.
 			var wg sync.WaitGroup
 			wg.Add(1)
+			defer wg.Wait()
+
 			go func() {
 				defer wg.Done()
 				slurp, _ := io.ReadAll(stderr)
@@ -530,7 +538,6 @@ func TestModeSpecificFlags(t *testing.T) {
 					prom.Process.Kill()
 					<-done
 				}
-				wg.Wait()
 				return
 			}
 
@@ -543,8 +550,6 @@ func TestModeSpecificFlags(t *testing.T) {
 			} else {
 				t.Errorf("unable to retrieve the exit status for prometheus: %v", err)
 			}
-
-			wg.Wait()
 		})
 	}
 }