Add test for subsetting a coverage axis

Author: Tara Drwenski

cdm/core/src/test/java/ucar/nc2/ft2/coverage/TestCoordAxisHelper.java

@@ -0,0 +1,64 @@
+package ucar.nc2.ft2.coverage;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import ucar.ma2.DataType;
+import ucar.ma2.InvalidRangeException;
+import ucar.ma2.Range;
+import ucar.nc2.constants.AxisType;
+import ucar.nc2.ft2.coverage.CoverageCoordAxis.Spacing;
+
+@RunWith(Parameterized.class)
+public class TestCoordAxisHelper {
+
+  @Parameterized.Parameters(name = "{0}, {1}")
+  public static List<Object[]> getTestParameters() {
+    return Arrays.asList(
+
+        new Object[] {Spacing.regularPoint, new double[] {0.0, 10.0, 20.0, 30.0, 40.0}},
+        new Object[] {Spacing.irregularPoint, new double[] {0.0, 5.0, 20.0, 30.0, 40.0}},
+        new Object[] {Spacing.regularInterval, new double[] {0.0, 10.0, 20.0, 30.0, 40.0}},
+        new Object[] {Spacing.contiguousInterval, new double[] {0.0, 5.0, 20.0, 30.0, 40.0}},
+        new Object[] {Spacing.discontiguousInterval, new double[] {0.0, 0.0, 20.0, 30.0, 40.0, 40.0, 50.0, 50.0}}
+
+    );
+  }
+
+  private final Spacing spacing;
+  private final double[] values;
+
+  public TestCoordAxisHelper(Spacing spacing, double[] values) {
+    this.spacing = spacing;
+    this.values = values;
+  }
+
+  @Test
+  public void shouldSubsetAxisByRange() throws InvalidRangeException {
+    final AxisType axisType = AxisType.Time;
+    final double resolution = values[1] - values[0];
+
+    final CoverageCoordAxisBuilder coverageCoordAxisBuilder = new CoverageCoordAxisBuilder("name", "unit",
+        "description", DataType.DOUBLE, axisType, null, CoverageCoordAxis.DependenceType.independent, null, spacing,
+        values.length, values[0], values[values.length - 1], resolution, values, null);
+    final CoverageCoordAxis1D coverageCoordAxis = new CoverageCoordAxis1D(coverageCoordAxisBuilder);
+    final CoordAxisHelper coordAxisHelper = new CoordAxisHelper(coverageCoordAxis);
+
+    final Range subsetRange = new Range(1, 3);
+    final CoverageCoordAxisBuilder subsetBuilder = coordAxisHelper.subsetByIndex(subsetRange);
+    assertThat(subsetBuilder).isNotNull();
+    assertThat(subsetBuilder.axisType).isEqualTo(axisType);
+    assertThat(subsetBuilder.startValue).isEqualTo(values[subsetRange.first()]);
+    assertThat(subsetBuilder.endValue).isEqualTo(values[subsetRange.last()]);
+
+    if (spacing == Spacing.regularPoint || spacing == Spacing.regularInterval) {
+      assertThat(subsetBuilder.values).isNull();
+    } else {
+      assertThat(subsetBuilder.values).isNotNull();
+    }
+  }
+}