Merge pull request #426 from apache/tdigest

tdigest cross-language test

tdigest/test/CMakeLists.txt

@@ -41,6 +41,13 @@ target_sources(tdigest_test
     tdigest_custom_allocator_test.cpp
 )
 
+if (SERDE_COMPAT)
+target_sources(tdigest_test
+  PRIVATE
+    tdigest_deserialize_from_java_test.cpp
+)
+endif()
+
 if (GENERATE)
 target_sources(tdigest_test
   PRIVATE

tdigest/test/tdigest_deserialize_from_java_test.cpp

@@ -0,0 +1,54 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+#include <catch2/catch.hpp>
+#include <fstream>
+
+#include "tdigest.hpp"
+
+namespace datasketches {
+
+// assume the binary sketches for this test have been generated by datasketches-java code
+// in the subdirectory called "java" in the root directory of this project
+static std::string testBinaryInputPath = std::string(TEST_BINARY_INPUT_PATH) + "../../java/";
+
+TEST_CASE("tdigest double", "[serde_compat]") {
+  const unsigned n_arr[] = {0, 1, 10, 100, 1000, 10000, 100000, 1000000};
+  for (const unsigned n: n_arr) {
+    std::ifstream is;
+    is.exceptions(std::ios::failbit | std::ios::badbit);
+    is.open(testBinaryInputPath + "tdigest_double_n" + std::to_string(n) + "_java.sk", std::ios::binary);
+    const auto td = tdigest<double>::deserialize(is);
+    REQUIRE(td.is_empty() == (n == 0));
+    REQUIRE(td.get_total_weight() == n);
+    if (n > 0) {
+      REQUIRE(td.get_min_value() == 1.0);
+      REQUIRE(td.get_max_value() == static_cast<double>(n));
+      REQUIRE(td.get_rank(0) == 0);
+      REQUIRE(td.get_rank(n + 1) == 1);
+      if (n == 1) {
+        REQUIRE(td.get_rank(n) == 0.5);
+      } else {
+        REQUIRE(td.get_rank(n / 2) == Approx(0.5).margin(0.05));
+      }
+    }
+  }
+}
+
+} /* namespace datasketches */