treewide: use Fatal in tests instead of Error

Error doesn't return the goroutine, but these cases are final and should end the test case.

Change-Id: I9d87e268b56acd7d1ff5883bb82bf3d74c309176
Reviewed-on: https://review.monogon.dev/c/monogon/+/4044
Reviewed-by: Jan Schär <jan@monogon.tech>
Tested-by: Jenkins CI
diff --git a/osbase/kmod/manager_test.go b/osbase/kmod/manager_test.go
index 2169703..05f7826 100644
--- a/osbase/kmod/manager_test.go
+++ b/osbase/kmod/manager_test.go
@@ -19,22 +19,22 @@
 	}
 	t.Run("LoadExampleModule", func(t *testing.T) {
 		if err := mgr.LoadModule("r8169"); err != nil {
-			t.Error(err)
+			t.Fatal(err)
 		}
 		if _, err := os.Stat("/sys/module/r8169"); err != nil {
-			t.Error("module load returned success, but module not in sysfs")
+			t.Fatal("module load returned success, but module not in sysfs")
 		}
 	})
 	t.Run("LoadNonexistentModule", func(t *testing.T) {
 		err := mgr.LoadModule("definitelynomodule")
 		var notFoundErr *ErrNotFound
 		if !errors.As(err, &notFoundErr) {
-			t.Errorf("expected ErrNotFound, got %v", err)
+			t.Fatalf("expected ErrNotFound, got %v", err)
 		}
 	})
 	t.Run("LoadModuleTwice", func(t *testing.T) {
 		if err := mgr.LoadModule("r8169"); err != nil {
-			t.Error(err)
+			t.Fatal(err)
 		}
 	})
 	// TODO(lorenz): Should test loading dependencies here, but we currently
@@ -42,10 +42,10 @@
 	// just for this.
 	t.Run("LoadDeviceModule", func(t *testing.T) {
 		if err := mgr.LoadModulesForDevice("pci:v00008086d00001591sv00001043sd000085F0bc02sc00i00"); err != nil {
-			t.Error(err)
+			t.Fatal(err)
 		}
 		if _, err := os.Stat("/sys/module/ice"); err != nil {
-			t.Error("module load returned success, but module not in sysfs")
+			t.Fatalf("module load returned success, but module not in sysfs")
 		}
 	})
 }