engine-manager: state the over-long query test's two expectations separately

One condition checked both that there was an error and what it said. Split, the test fails plainly if the query is answered, and compares the message only once there is one -- comparing a nil error's message would panic instead of failing.

Signed-off-by: Terve <ntervalon@nvidia.com>

Author: Noah-Tervalon-Nvidia

services/nvpair-engine-manager/catalog_test.go

@@ -639,8 +639,11 @@ func TestOverLongSearchIsRefused(t *testing.T) {
 
 	query := strings.TrimSpace(strings.Repeat("private ", maxCatalogQuery/len("private ")+1))
 	_, err := c.Catalog(context.Background(), "llamacpp", "", "", query)
-	if err == nil || err.Error() != "a model search is limited to 100 characters" {
-		t.Errorf("a %d-character query: error %v, want the limit stated without the query", len(query), err)
+	if err == nil {
+		t.Fatalf("a %d-character query was answered", len(query))
+	}
+	if got, want := err.Error(), "a model search is limited to 100 characters"; got != want {
+		t.Errorf("error %q, want %q", got, want)
 	}
 	if got := requests(); len(got) != 0 {
 		t.Errorf("an over-long query reached the upstream: %v", got)