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/pstore/pstore_test.go b/osbase/pstore/pstore_test.go
index d4024e6..36423f3 100644
--- a/osbase/pstore/pstore_test.go
+++ b/osbase/pstore/pstore_test.go
@@ -110,10 +110,10 @@
 			dumps, err := getKmsgDumpsFromFS(c.inputFS)
 			switch {
 			case err == nil && c.expectErr:
-				t.Error("Expected error, but got none")
+				t.Fatal("Expected error, but got none")
 				return
 			case err != nil && !c.expectErr:
-				t.Errorf("Got unexpected error: %v", err)
+				t.Fatalf("Got unexpected error: %v", err)
 				return
 			case err != nil && c.expectErr:
 				// Got expected error