Add Histogram Matching RDD Unit Tests

spark/src/test/scala/geotrellis/spark/matching/RDDHistogramMatchingSpec.scala

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+/*
+ * Copyright (c) 2016 Azavea.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package geotrellis.spark.matching
+
+import geotrellis.raster._
+import geotrellis.spark._
+import geotrellis.raster.histogram.StreamingHistogram
+
+import org.scalatest._
+
+
+class RDDHistogramMatchingSpec extends FunSpec
+    with Matchers
+    with TestEnvironment {
+
+    val sourceHistogram = {
+      val h = StreamingHistogram(42)
+      h.countItem(1, 1)
+      h.countItem(2, 2)
+      h.countItem(4, 3)
+      h.countItem(8, 4)
+      h.countItem(16, 5)
+      h
+    }
+
+    val targetHistogram = {
+      val h = StreamingHistogram(42)
+      h.countItem(1, 1)
+      h.countItem(2, 2)
+      h.countItem(3, 3)
+      h.countItem(4, 4)
+      h.countItem(5, 5)
+      h
+    }
+
+  val sourceHistograms = List(sourceHistogram, sourceHistogram)
+  val targetHistograms = List(targetHistogram, targetHistogram)
+
+  describe("RDD Histogram Matching") {
+
+    it("should work with floating-point rasters") {
+      val tile1 = DoubleArrayTile(Array[Double](16, 1, 2), 1, 3).asInstanceOf[Tile]
+      val tile2 = DoubleArrayTile(Array[Double](4, 8, 16), 1, 3).asInstanceOf[Tile]
+      val rdd = ContextRDD(sc.parallelize(List((SpatialKey(0,0), tile1), (SpatialKey(0,0), tile2))), 33)
+      val actual = rdd.matchHistogram(sourceHistogram, targetHistogram).flatMap({ _._2.toArray.toList }).collect
+      val expected = List[Double](5, 1, 2, 3, 4, 5)
+
+      actual should be (expected)
+    }
+
+    it("should work with unsigned integral rasters") {
+      val tile1 = UShortArrayTile(Array[Short](16, 1, 2), 1, 3).asInstanceOf[Tile]
+      val tile2 = UShortArrayTile(Array[Short](4, 8, 16), 1, 3).asInstanceOf[Tile]
+      val rdd = ContextRDD(sc.parallelize(List((SpatialKey(0,0), tile1), (SpatialKey(0,0), tile2))), 33)
+      val actual = rdd.matchHistogram(sourceHistogram, targetHistogram).flatMap({ _._2.toArray.toList }).collect
+      val expected = List[Double](5, 1, 2, 3, 4, 5)
+
+      actual should be (expected)
+    }
+
+    it("should work with signed integral rasters") {
+      val tile1 = ShortArrayTile(Array[Short](16, 1, 2), 1, 3).asInstanceOf[Tile]
+      val tile2 = ShortArrayTile(Array[Short](4, 8, 16), 1, 3).asInstanceOf[Tile]
+      val rdd = ContextRDD(sc.parallelize(List((SpatialKey(0,0), tile1), (SpatialKey(0,0), tile2))), 33)
+      val actual = rdd.matchHistogram(sourceHistogram, targetHistogram).flatMap({ _._2.toArray.toList }).collect
+      val expected = List[Double](5, 1, 2, 3, 4, 5)
+
+      actual should be (expected)
+    }
+
+    it("should work with multiband tiles") {
+      val band1 = ShortArrayTile(Array[Short](16, 1, 2), 1, 3).asInstanceOf[Tile]
+      val band2 = ShortArrayTile(Array[Short](4, 8, 16), 1, 3).asInstanceOf[Tile]
+      val tile1 = ArrayMultibandTile(band1, band2)
+      val tile2 = ArrayMultibandTile(band2, band1)
+      val rdd = ContextRDD(sc.parallelize(List((SpatialKey(0,0), tile1), (SpatialKey(0,0), tile2))), 33)
+      val actual = rdd
+        .matchHistogram(sourceHistograms, targetHistograms)
+        .flatMap({ case (_, v) =>
+          v.bands.flatMap({ _.toArray.toList })
+        }).collect
+      val expected = List[Double](5, 1, 2, 3, 4, 5, 3, 4, 5, 5, 1, 2)
+
+      actual should be (expected)
+    }
+
+  }
+}