Add impl to parse focused attr

pmd-test-schema/src/main/java/net/sourceforge/pmd/test/schema/BaseTestParserImpl.java

@@ -100,6 +100,13 @@ class BaseTestParserImpl {
 
         descriptor.setDisabled(disabled);
 
+
+        boolean focused = parseBoolAttribute(testCode, "focused", false, err,
+                                             "Attribute focused is used, do not forget to remove it when checking in sources");
+
+        descriptor.setFocused(focused);
+
+
         Properties properties = parseRuleProperties(testCode, descriptor.getRule(), err);
         descriptor.getProperties().putAll(properties);
 

pmd-test-schema/src/main/java/net/sourceforge/pmd/test/schema/RuleTestCollection.java

@@ -28,4 +28,17 @@ public class RuleTestCollection {
         return Collections.unmodifiableList(tests);
     }
 
+    /**
+     * Returns the last test of the collection which is focused.
+     */
+    public RuleTestDescriptor getFocusedTestOrNull() {
+        RuleTestDescriptor focused = null;
+        for (RuleTestDescriptor test : tests) {
+            if (test.isFocused()) {
+                focused = test;
+            }
+        }
+        return focused;
+    }
+
 }

pmd-test-schema/src/main/java/net/sourceforge/pmd/test/schema/RuleTestDescriptor.java

@@ -16,6 +16,7 @@ import net.sourceforge.pmd.lang.LanguageVersion;
 public class RuleTestDescriptor {
 
     private boolean disabled;
+    private boolean focused;
     private String description;
     private LanguageVersion languageVersion;
     private final Properties properties = new Properties();
@@ -106,4 +107,12 @@ public class RuleTestDescriptor {
     public List<String> getExpectedMessages() {
         return expectedMessages;
     }
+
+    public boolean isFocused() {
+        return focused;
+    }
+
+    public void setFocused(boolean focused) {
+        this.focused = focused;
+    }
 }

pmd-test/src/main/java/net/sourceforge/pmd/testframework/RuleTestRunner.java

@@ -5,9 +5,7 @@
 package net.sourceforge.pmd.testframework;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.Comparator;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.concurrent.ConcurrentHashMap;
 
@@ -26,6 +24,8 @@ import org.junit.runners.model.InitializationError;
 import org.junit.runners.model.Statement;
 
 import net.sourceforge.pmd.Rule;
+import net.sourceforge.pmd.test.schema.RuleTestCollection;
+import net.sourceforge.pmd.test.schema.RuleTestDescriptor;
 
 /**
  * A JUnit Runner, that executes all declared rule tests in the class.
@@ -64,18 +64,18 @@ public class RuleTestRunner extends ParentRunner<TestDescriptor> {
     @Override
     protected List<TestDescriptor> getChildren() {
         List<Rule> rules = new ArrayList<>(instance.getRules());
-        Collections.sort(rules, new Comparator<Rule>() {
-            @Override
-            public int compare(Rule o1, Rule o2) {
-                return o1.getName().compareTo(o2.getName());
-            }
-        });
+        rules.sort(Comparator.comparing(Rule::getName));
 
-        List<TestDescriptor> tests = new LinkedList<>();
+        List<TestDescriptor> tests = new ArrayList<>();
         for (Rule r : rules) {
-            TestDescriptor[] ruleTests = instance.extractTestsFromXml(r);
-            for (TestDescriptor t : ruleTests) {
-                tests.add(t);
+            RuleTestCollection ruleTests = instance.parseTestCollection(r);
+            RuleTestDescriptor focused = ruleTests.getFocusedTestOrNull();
+            for (RuleTestDescriptor t : ruleTests.getTests()) {
+                TestDescriptor td = new TestDescriptor(t);
+                if (focused != null && focused != t) {
+                    td.setRegressionTest(false); // disable it
+                }
+                tests.add(td);
             }
         }
 

pmd-test/src/main/java/net/sourceforge/pmd/testframework/RuleTst.java

@@ -290,6 +290,16 @@ public abstract class RuleTst {
         return extractTestsFromXml(rule, testsFileName);
     }
 
+    /**
+     * Extract a set of tests from an XML file. The file should be
+     * ./xml/RuleName.xml relative to the test class. The format is defined in
+     * test-data.xsd.
+     */
+    RuleTestCollection parseTestCollection(Rule rule) {
+        String testsFileName = getCleanRuleName(rule);
+        return parseTestXml(rule, testsFileName, "xml/");
+    }
+
     public TestDescriptor[] extractTestsFromXml(Rule rule, String testsFileName) {
         return extractTestsFromXml(rule, testsFileName, "xml/");
     }

pmd-test/src/main/java/net/sourceforge/pmd/testframework/TestDescriptor.java

@@ -32,6 +32,7 @@ public class TestDescriptor {
     private boolean isRegressionTest = true;
     private boolean useAuxClasspath = true;
     private int numberInDocument = -1;
+    private boolean isFocused = false;
 
     public TestDescriptor() {
         // Empty default descriptor added to please mvn surefire plugin
@@ -62,6 +63,7 @@ public class TestDescriptor {
         this.numberInDocument = td.getIndex();
         this.properties = td.getProperties();
         this.languageVersion = td.getLanguageVersion();
+        this.isFocused = td.isFocused();
     }
 
     public int getNumberInDocument() {