Add test.

test/unit/CMakeLists.txt

@@ -234,6 +234,7 @@ PDAL_ADD_TEST(pdal_filters_mongoexpression_test
 
 PDAL_ADD_TEST(pdal_filters_ferry_test FILES filters/FerryFilterTest.cpp)
 PDAL_ADD_TEST(pdal_filters_groupby_test FILES filters/GroupByFilterTest.cpp)
+PDAL_ADD_TEST(pdal_filters_ht_test FILES filters/HeadTailFilterTest.cpp)
 PDAL_ADD_TEST(pdal_filters_info_test FILES filters/InfoFilterTest.cpp)
 PDAL_ADD_TEST(pdal_filters_neighborclassifier_test FILES filters/NeighborClassifierFilterTest.cpp)
 PDAL_ADD_TEST(pdal_filters_locate_test FILES filters/LocateFilterTest.cpp)

test/unit/filters/HeadTailFilterTest.cpp

@@ -0,0 +1,96 @@
+/******************************************************************************
+* Copyright (c) 2019, Hobu Inc. (info@hobu.co)
+*
+* All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following
+* conditions are met:
+*
+*     * Redistributions of source code must retain the above copyright
+*       notice, this list of conditions and the following disclaimer.
+*     * Redistributions in binary form must reproduce the above copyright
+*       notice, this list of conditions and the following disclaimer in
+*       the documentation and/or other materials provided
+*       with the distribution.
+*     * Neither the name of Hobu, Inc. nor the
+*       names of its contributors may be used to endorse or promote
+*       products derived from this software without specific prior
+*       written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+* OF SUCH DAMAGE.
+****************************************************************************/
+
+#include <pdal/pdal_test_main.hpp>
+
+#include <pdal/StageFactory.hpp>
+#include <io/FauxReader.hpp>
+#include <filters/HeadFilter.hpp>
+#include <filters/TailFilter.hpp>
+
+#include "Support.hpp"
+
+using namespace pdal;
+
+
+void testFilter(bool head, bool invert)
+{
+    BOX3D srcBounds(0.0, 0.0, 1.0, 0.0, 0.0, 10.0);
+
+    Options ops;
+    ops.add("bounds", srcBounds);
+    ops.add("mode", "ramp");
+    ops.add("count", 10);
+
+    FauxReader reader;
+    reader.setOptions(ops);
+
+    Options ops2;
+    ops2.add("count", 4);
+    ops2.add("invert", invert);
+
+    StageFactory fac;
+    Stage& f = *(fac.createStage(head ? "filters.head" : "filters.tail"));
+    f.setOptions(ops2);
+    f.setInput(reader);
+
+    PointTable t;
+    f.prepare(t);
+    PointViewSet s = f.execute(t);
+    PointViewPtr v = *s.begin();
+    EXPECT_EQ(v->size(), invert ? 6u : 4u);
+
+    int min { 0 };
+    if (head)
+        min = invert ? 5 : 1;
+    else
+        min = invert ? 1 : 7;
+
+    for (PointId i = 0; i < v->size(); ++i)
+    {
+        int z = v->getFieldAs<int>(Dimension::Id::Z, i);
+        EXPECT_EQ(z, min);
+        min++;
+    }
+
+}
+
+TEST(HeadTailFilterTest, t1)
+{
+    testFilter(true, true);
+    testFilter(true, false);
+    testFilter(false, true);
+    testFilter(false, false);
+}
+