From 0edbe9594c4f1ff8c70dc81eb38141a12878ad04 Mon Sep 17 00:00:00 2001
From: David Dixon-Peugh <dpeugh@users.sourceforge.net>
Date: Wed, 28 Aug 2002 21:20:41 +0000
Subject: [PATCH] Added test to check for Metrics on the Report.

git-svn-id: https://pmd.svn.sourceforge.net/svnroot/pmd/trunk@816 51baf565-9d33-0410-a72c-fc3788e3496d
---
 .../pmd/stat/StatisticalRuleTest.java         | 27 ++++++++++++++++++-
 .../sourceforge/pmd/stat/StatisticalRule.java | 18 ++++++-------
 2 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/pmd/regress/test/net/sourceforge/pmd/stat/StatisticalRuleTest.java b/pmd/regress/test/net/sourceforge/pmd/stat/StatisticalRuleTest.java
index 4d912aa6cd..fc38de90c3 100644
--- a/pmd/regress/test/net/sourceforge/pmd/stat/StatisticalRuleTest.java
+++ b/pmd/regress/test/net/sourceforge/pmd/stat/StatisticalRuleTest.java
@@ -1,5 +1,6 @@
 package test.net.sourceforge.pmd.stat;
 
+import java.util.Iterator;
 import java.util.List;
 import java.util.ArrayList;
 import java.util.Random;
@@ -60,7 +61,7 @@ public class StatisticalRuleTest
 	
 		
 	public static final double MEAN = 499.5;
-	public static final double SIGMA = 288.8194;
+	public static final double SIGMA = 288.6750;
 	public static final int NUM_TESTS = 32;
 	
     public StatisticalRuleTest(String name) 
@@ -81,6 +82,30 @@ public class StatisticalRuleTest
 		}
     }
 
+	/**
+	 * This test verifies that the Stat rule creates a Metric,
+	 * with the proper values.
+	 */
+	public void testMetrics() throws Throwable
+	{
+		Report report = makeReport( IUT );
+		Iterator metrics = report.metrics();
+		
+		assertTrue( metrics.hasNext());
+		Object o = metrics.next();
+		
+		assertTrue( o instanceof Metric);
+		Metric m = (Metric) o;
+		
+		assertEquals("test.net.sourceforge.pmd.stat.MockStatisticalRule", 
+					m.getMetricName());
+		
+		assertEquals( 0.0, m.getLowValue(), 0.05 );
+		assertEquals( 999.0, m.getHighValue(), 0.05 );
+		assertEquals( MEAN, m.getAverage(), 0.05 );
+		assertEquals( SIGMA, m.getStandardDeviation(), 0.05 );
+	}
+	
 	/**
 	 * This returns a Random value for Sigma which will
 	 * return some values.
diff --git a/pmd/src/net/sourceforge/pmd/stat/StatisticalRule.java b/pmd/src/net/sourceforge/pmd/stat/StatisticalRule.java
index 2f363ec700..7a974c927d 100644
--- a/pmd/src/net/sourceforge/pmd/stat/StatisticalRule.java
+++ b/pmd/src/net/sourceforge/pmd/stat/StatisticalRule.java
@@ -24,11 +24,14 @@ public abstract class StatisticalRule extends AbstractRule {
 
     private int count = 0;
     private double total = 0.0;
-
+	private double totalSquared = 0.0;
+	
     public void addDataPoint( DataPoint point )
     {
 		count++;
 		total += point.getScore();
+		totalSquared += point.getScore() * point.getScore();
+		
 		dataPoints.add( point );
     }
     
@@ -61,8 +64,8 @@ public abstract class StatisticalRule extends AbstractRule {
 		
 		makeViolations(ctx, newPoints);
 		
-		double low = ((DataPoint) newPoints.first()).getScore();
-		double high = ((DataPoint) newPoints.last()).getScore();
+		double low = ((DataPoint) dataPoints.first()).getScore();
+		double high = ((DataPoint) dataPoints.last()).getScore();
 	
 		ctx.getReport().addMetric( new Metric( this.getName(), low, high,
 		                                       getMean(), getStdDev()));
@@ -77,13 +80,8 @@ public abstract class StatisticalRule extends AbstractRule {
 
 		Iterator points = dataPoints.iterator();
 
-    	while (points.hasNext()) {
-		    DataPoint point = (DataPoint) points.next();
-		    varTotal += ((point.getScore() - getMean()) *
-				 		 (point.getScore() - getMean()));	
-    	}                             	
-    	
-    	double variance = varTotal / count;
+		double variance = ((totalSquared / count) -
+						   (getMean() * getMean() ));    	
 		return Math.sqrt( variance );
 	}