Adding tests for new StrideReadings class.

MyTracksTest/src/com/google/android/apps/mytracks/services/sensors/StrideReadingsTest.java

@@ -0,0 +1,29 @@
+package com.google.android.apps.mytracks.services.sensors;
+
+import junit.framework.TestCase;
+
+public class StrideReadingsTest extends TestCase {
+  
+  public void testNoReadingOnStartup() {
+    StrideReadings strideReadings = new StrideReadings();
+    assertTrue(strideReadings.getCadence() == StrideReadings.CADENCE_NOT_AVAILABLE);
+  }
+  
+  public void testAverageCadenceAvailable() {
+    StrideReadings strideReadings = new StrideReadings();
+    for(int i=0;i<30;i++) {
+      strideReadings.updateStrideReading(i*1000, i*2);
+    }
+    assertTrue(strideReadings.getCadence() > 0);
+  }
+  
+  /* testing rollover at 127, just like the HxM seems to do it */
+  public void testRollover() {
+    StrideReadings strideReadings = new StrideReadings();
+    for(int i=0;i<=10;i++) {
+      strideReadings.updateStrideReading(i*1000, (120 + i*2) );
+    }
+    assertTrue(strideReadings.getCadence() > 0);
+  }
+
+}