ReadOnlyByHttpIT: Extend to cover both 'readonly' and 'readonly~readonly'

Change I297e79df2 fixed a bug where the DELETE request was not allowed
on 'readonly'. Extend the tests to cover this case.

Change-Id: I770495840f807582bdf2fa91bd934887cd4b7ce9
diff --git a/src/test/java/com/googlesource/gerrit/plugins/readonly/ReadOnlyByHttpIT.java b/src/test/java/com/googlesource/gerrit/plugins/readonly/ReadOnlyByHttpIT.java
index 9cc4f15..b078dae 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/readonly/ReadOnlyByHttpIT.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/readonly/ReadOnlyByHttpIT.java
@@ -17,22 +17,44 @@
 import static com.google.common.truth.Truth.assertThat;
 
 import com.google.gerrit.acceptance.RestResponse;
+import com.google.gerrit.server.config.GerritServerConfig;
+import com.google.gerrit.testutil.ConfigSuite;
+import com.google.inject.Inject;
+import org.eclipse.jgit.lib.Config;
 
 public class ReadOnlyByHttpIT extends AbstractReadOnlyTest {
+  @ConfigSuite.Default
+  public static Config withPluginNamePrefix() {
+    Config cfg = new Config();
+    cfg.setString("readonly", "test", "endpoint", "readonly~readonly");
+    return cfg;
+  }
+
+  @ConfigSuite.Config
+  public static Config withoutPluginNamePrefix() {
+    Config cfg = new Config();
+    cfg.setString("readonly", "test", "endpoint", "readonly");
+    return cfg;
+  }
+
+  @Inject @GerritServerConfig private Config config;
+
   @Override
   protected void setReadOnly(boolean readOnly) throws Exception {
+    String endpoint =
+        String.format("/config/server/%s", config.getString("readonly", "test", "endpoint"));
     String expectedStatus = readOnly ? "on" : "off";
     RestResponse response;
     if (readOnly) {
-      response = adminRestSession.put("/config/server/readonly~readonly");
+      response = adminRestSession.put(endpoint);
       response.assertOK();
       assertThat(response.getEntityContent()).contains(expectedStatus);
     } else {
-      response = adminRestSession.delete("/config/server/readonly~readonly");
+      response = adminRestSession.delete(endpoint);
       response.assertOK();
       assertThat(response.getEntityContent()).contains(expectedStatus);
     }
-    response = adminRestSession.get("/config/server/readonly~readonly");
+    response = adminRestSession.get(endpoint);
     response.assertOK();
     assertThat(response.getEntityContent()).contains(expectedStatus);
   }