Fix gerrit_common_test.pl

* Ensure we always load test cases, otherwise
  there is a false positive.

* Fix the package to correctly be "gerrit".

* Drop unnecessary quotes from Prolog package
  statements. The bare text is a valid symbol.

Change-Id: I331ca90e050dc6d20e192c522f96893078102e59
diff --git a/gerrit-server/src/main/prolog/gerrit_common.pl b/gerrit-server/src/main/prolog/gerrit_common.pl
index bfcb1fd..ba0336e 100644
--- a/gerrit-server/src/main/prolog/gerrit_common.pl
+++ b/gerrit-server/src/main/prolog/gerrit_common.pl
@@ -12,7 +12,7 @@
 %% See the License for the specific language governing permissions and
 %% limitations under the License.
 
-:- package 'gerrit'.
+:- package gerrit.
 '$init' :- init.
 
 
diff --git a/gerrit-server/src/test/java/com/google/gerrit/rules/GerritCommonTest.java b/gerrit-server/src/test/java/com/google/gerrit/rules/GerritCommonTest.java
index 389b393..2b8dad5 100644
--- a/gerrit-server/src/test/java/com/google/gerrit/rules/GerritCommonTest.java
+++ b/gerrit-server/src/test/java/com/google/gerrit/rules/GerritCommonTest.java
@@ -34,7 +34,7 @@
         verifiedCategory()
     ));
 
-    load("gerrit_common_test.pl", new AbstractModule() {
+    load("gerrit", "gerrit_common_test.pl", new AbstractModule() {
       @Override
       protected void configure() {
         bind(ApprovalTypes.class).toInstance(types);
diff --git a/gerrit-server/src/test/java/com/google/gerrit/rules/PrologTestCase.java b/gerrit-server/src/test/java/com/google/gerrit/rules/PrologTestCase.java
index d822a19..9b75dba 100644
--- a/gerrit-server/src/test/java/com/google/gerrit/rules/PrologTestCase.java
+++ b/gerrit-server/src/test/java/com/google/gerrit/rules/PrologTestCase.java
@@ -43,7 +43,7 @@
   private List<Term> tests;
   protected PrologEnvironment env;
 
-  protected void load(String prologResource, Module... modules)
+  protected void load(String pkg, String prologResource, Module... modules)
       throws FileNotFoundException, CompileException {
     ArrayList<Module> moduleList = new ArrayList<Module>();
     moduleList.add(new PrologModule());
@@ -58,7 +58,7 @@
 
     consult(getClass(), prologResource);
 
-    pkg = myPackage();
+    this.pkg = pkg;
     hasSetup = has("setup");
     hasTeardown = has("teardown");
 
@@ -70,6 +70,7 @@
     for (Term[] pair : env.all(Prolog.BUILTIN, "clause", head, new VariableTerm())) {
       tests.add(pair[0]);
     }
+    assertTrue("has tests", tests.size() > 0);
   }
 
   protected void consult(Class<?> clazz, String prologResource)
@@ -85,11 +86,6 @@
     }
   }
 
-  private String myPackage() {
-    String pkg = getClass().getName();
-    return pkg.substring(0, pkg.lastIndexOf('.'));
-  }
-
   private boolean has(String name) {
     StructureTerm head = SymbolTerm.create(pkg, name, 0);
     return env.execute(Prolog.BUILTIN, "clause", head, new VariableTerm());
diff --git a/gerrit-server/src/test/resources/com/google/gerrit/rules/gerrit_common_test.pl b/gerrit-server/src/test/resources/com/google/gerrit/rules/gerrit_common_test.pl
index ccf4835..6aae509 100644
--- a/gerrit-server/src/test/resources/com/google/gerrit/rules/gerrit_common_test.pl
+++ b/gerrit-server/src/test/resources/com/google/gerrit/rules/gerrit_common_test.pl
@@ -12,7 +12,7 @@
 %% See the License for the specific language governing permissions and
 %% limitations under the License.
 
-:- package 'gerrit'.
+:- package gerrit.
 
 
 %% not_same