Do not use color for unchanged coverage #777

plugin/src/main/java/io/jenkins/plugins/coverage/metrics/steps/CoverageBuildAction.java

@@ -18,7 +18,6 @@
 import org.apache.commons.lang3.math.Fraction;
 
 import edu.hm.hafner.coverage.Metric;
-import edu.hm.hafner.coverage.Metric.MetricTendency;
 import edu.hm.hafner.coverage.Node;
 import edu.hm.hafner.coverage.Value;
 import edu.hm.hafner.echarts.ChartModelConfiguration;
@@ -544,18 +543,23 @@ public String formatDelta(final Baseline baseline, final Metric metric) {
      * @param metric
      *         the metric to check
      *
-     * @return {@code true} if the trend is positive, {@code false} otherwise
+     * @return a positive value if the trend is positive, a negative value if the trend is negative, or {@code 0} if there is no significant change in the trend
      */
     @SuppressWarnings("unused") // Called by jelly view
-    public boolean isPositiveTrend(final Baseline baseline, final Metric metric) {
+    public double getTrend(final Baseline baseline, final Metric metric) {
         var delta = getDelta(baseline, metric);
         if (delta.isPresent()) {
-            if (delta.get().compareTo(Fraction.ZERO) > 0) {
-                return metric.getTendency() == MetricTendency.LARGER_IS_BETTER;
+            double deltaValue = delta.get().doubleValue();
+            if (-0.001 < deltaValue && deltaValue < 0.001) {
+                // for var(--text-color)
+                return 0;
+            }
+            else {
+                // for var(--red or --green)
+                return deltaValue;
             }
-            return metric.getTendency() == MetricTendency.SMALLER_IS_BETTER;
         }
-        return true;
+        return 0; // default to zero
     }
 
     /**

plugin/src/main/resources/coverage/coverage-summary.jelly

@@ -60,11 +60,14 @@
             <li>${formatter.formatValueWithMetric(value)}
               <j:if test="${it.hasDelta(baseline, value.metric)}">
                 <j:choose>
-                  <j:when test="${it.isPositiveTrend(baseline, value.metric)}">
+                  <j:when test="${it.getTrend(baseline, value.metric) gt 0}">
                     <j:set var="color" value="var(--green)"/>
                   </j:when>
-                  <j:otherwise>
+                  <j:when test="${it.getTrend(baseline, value.metric) lt 0}">
                     <j:set var="color" value="var(--red)"/>
+                  </j:when>
+                  <j:otherwise>
+                    <j:set var="color" value="var(--text-color)"/>
                   </j:otherwise>
                 </j:choose>
                 <span style="color: ${color}">(${it.formatDelta(baseline, value.metric)})</span>

plugin/src/test/java/io/jenkins/plugins/coverage/metrics/steps/CoverageBuildActionTest.java

@@ -2,6 +2,7 @@
 
 import java.util.List;
 import java.util.TreeMap;
+import java.util.Optional;
 
 import org.apache.commons.lang3.StringUtils;
 import org.apache.commons.lang3.math.Fraction;
@@ -30,6 +31,24 @@
  */
 @DefaultLocale("en")
 class CoverageBuildActionTest {
+    private CoverageBuildAction createCoverageBuildActionWithDelta(final Metric metric, final Optional<Fraction> delta) {
+        Node module = new ModuleNode("module");
+
+        var coverageBuilder = new CoverageBuilder();
+        var percent = coverageBuilder.setMetric(metric).setCovered(1).setMissed(1).build();
+
+        module.addValue(percent);
+
+        var deltas = new TreeMap<Metric, Fraction>();
+        delta.ifPresent(d -> deltas.put(metric, d));
+
+        var coverages = List.of(percent);
+
+        return spy(new CoverageBuildAction(mock(FreeStyleBuild.class), CoverageRecorder.DEFAULT_ID,
+                StringUtils.EMPTY, StringUtils.EMPTY, module, new QualityGateResult(),
+                createLog(), "-", deltas, coverages, deltas, coverages, deltas, coverages, false));
+    }
+
     @Test
     void shouldNotLoadResultIfCoverageValuesArePersistedInAction() {
         Node module = new ModuleNode("module");
@@ -88,4 +107,28 @@ void shouldCreateViewModel() {
         assertThat(action.getTarget()).extracting(CoverageViewModel::getNode).isSameAs(root);
         assertThat(action.getTarget()).extracting(CoverageViewModel::getOwner).isSameAs(action.getOwner());
     }
+
+    @Test
+    void shouldReturnPositiveTrendForLineMetric() {
+        CoverageBuildAction action = createCoverageBuildActionWithDelta(Metric.LINE, Optional.of(Fraction.getFraction(1, 1000)));
+        assertThat(action.getTrend(Baseline.PROJECT, Metric.LINE)).isPositive();
+    }
+
+    @Test
+    void shouldReturnNegativeTrendForLineMetric() {
+        CoverageBuildAction action = createCoverageBuildActionWithDelta(Metric.LINE, Optional.of(Fraction.getFraction(-1, 1000)));
+        assertThat(action.getTrend(Baseline.PROJECT, Metric.LINE)).isNegative();
+    }
+
+    @Test
+    void shouldReturnZeroForDeltaWithinBoundaries() {
+        CoverageBuildAction action = createCoverageBuildActionWithDelta(Metric.LINE, Optional.of(Fraction.getFraction(9, 10_000)));
+        assertThat(action.getTrend(Baseline.PROJECT, Metric.LINE)).isZero();
+    }
+
+    @Test
+    void shouldReturnZeroWhenDeltaIsNotPresentForGivenMetric() {
+        CoverageBuildAction action = createCoverageBuildActionWithDelta(Metric.LINE, Optional.empty());
+        assertThat(action.getTrend(Baseline.PROJECT, Metric.LINE)).isZero();
+    }
 }