Small cleanup for mock tests. (#10085)

tests/cpp/CMakeLists.txt

@@ -29,8 +29,8 @@ if(PLUGIN_SYCL)
     ${xgboost_SOURCE_DIR}/rabit/include)
 
   target_compile_definitions(plugin_sycl_test PUBLIC -DXGBOOST_USE_SYCL=1)
-
   target_link_libraries(plugin_sycl_test PUBLIC -fsycl)
+  target_link_libraries(plugin_sycl_test PRIVATE ${GTEST_LIBRARIES})
 
   set_target_properties(plugin_sycl_test PROPERTIES
     COMPILE_FLAGS -fsycl

tests/cpp/data/test_metainfo.cc

@@ -1,6 +1,9 @@
-// Copyright 2016-2021 by Contributors
+/**
+ * Copyright 2016-2024, XGBoost contributors
+ */
 #include "test_metainfo.h"
 
+#include <gmock/gmock.h>
 #include <dmlc/io.h>
 #include <xgboost/data.h>
 
@@ -9,7 +12,7 @@
 
 #include "../../../src/common/version.h"
 #include "../filesystem.h"  // dmlc::TemporaryDirectory
-#include "../helpers.h"
+#include "../helpers.h"     // for GMockTHrow
 #include "xgboost/base.h"
 
 namespace xgboost {
@@ -46,6 +49,8 @@ TEST(MetaInfo, GetSet) {
 
 TEST(MetaInfo, GetSetFeature) {
   xgboost::MetaInfo info;
+  ASSERT_THAT([&] { info.SetFeatureInfo("", nullptr, 0); },
+              GMockThrow("Unknown feature info name"));
   EXPECT_THROW(info.SetFeatureInfo("", nullptr, 0), dmlc::Error);
   EXPECT_THROW(info.SetFeatureInfo("foo", nullptr, 0), dmlc::Error);
   EXPECT_NO_THROW(info.SetFeatureInfo("feature_name", nullptr, 0));
@@ -86,7 +91,8 @@ void VerifyGetSetFeatureColumnSplit() {
   std::transform(types.cbegin(), types.cend(), c_types.begin(),
                  [](auto const &str) { return str.c_str(); });
   info.num_col_ = kCols;
-  EXPECT_THROW(info.SetFeatureInfo(u8"feature_type", c_types.data(), c_types.size()), dmlc::Error);
+  ASSERT_THAT([&] { info.SetFeatureInfo(u8"feature_type", c_types.data(), c_types.size()); },
+              GMockThrow("Length of feature_type must be equal to number of columns"));
   info.num_col_ = kCols * world_size;
   EXPECT_NO_THROW(info.SetFeatureInfo(u8"feature_type", c_types.data(), c_types.size()));
   std::vector<std::string> expected_type_names{u8"float", u8"c",     u8"float",
@@ -103,7 +109,8 @@ void VerifyGetSetFeatureColumnSplit() {
   std::transform(names.cbegin(), names.cend(), c_names.begin(),
                  [](auto const &str) { return str.c_str(); });
   info.num_col_ = kCols;
-  EXPECT_THROW(info.SetFeatureInfo(u8"feature_name", c_names.data(), c_names.size()), dmlc::Error);
+  ASSERT_THAT([&] { info.SetFeatureInfo(u8"feature_name", c_names.data(), c_names.size()); },
+              GMockThrow("Length of feature_name must be equal to number of columns"));
   info.num_col_ = kCols * world_size;
   EXPECT_NO_THROW(info.SetFeatureInfo(u8"feature_name", c_names.data(), c_names.size()));
   std::vector<std::string> expected_names{u8"0.feature0", u8"0.feature1", u8"1.feature0",

tests/cpp/helpers.h

@@ -1,8 +1,9 @@
 /**
- * Copyright 2016-2024 by XGBoost contributors
+ * Copyright 2016-2024, XGBoost contributors
  */
 #pragma once
 
+#include <gmock/gmock.h>
 #include <gtest/gtest.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -573,30 +574,7 @@ class DeclareUnifiedDistributedTest(MetricTest) : public BaseMGPUTest{};
 
 inline DeviceOrd FstCU() { return DeviceOrd::CUDA(0); }
 
-/**
- * @brief poor man's gmock for message matching.
- *
- * @tparam Error The type of expected execption.
- *
- * @param submsg A substring of the actual error message.
- * @param fn The function that throws Error
- */
-template <typename Error, typename Fn>
-void ExpectThrow(std::string submsg, Fn&& fn) {
-  try {
-    fn();
-  } catch (Error const& exc) {
-    auto actual = std::string{exc.what()};
-    ASSERT_NE(actual.find(submsg), std::string::npos)
-        << "Expecting substring `" << submsg << "` from the error message."
-        << " Got:\n"
-        << actual << "\n";
-    return;
-  } catch (std::exception const& exc) {
-    auto actual = exc.what();
-    ASSERT_TRUE(false) << "An unexpected type of exception is thrown. what:" << actual;
-    return;
-  }
-  ASSERT_TRUE(false) << "No exception is thrown";
+inline auto GMockThrow(StringView msg) {
+  return ::testing::ThrowsMessage<dmlc::Error>(::testing::HasSubstr(msg));
 }
 }  // namespace xgboost

tests/cpp/plugin/federated/test_federated_comm.cc

@@ -1,5 +1,5 @@
 /**
- * Copyright 2022-2023, XGBoost contributors
+ * Copyright 2022-2024, XGBoost contributors
  */
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
@@ -9,7 +9,7 @@
 
 #include "../../../../plugin/federated/federated_comm.h"
 #include "../../collective/test_worker.h"  // for SocketTest
-#include "../../helpers.h"                 // for ExpectThrow
+#include "../../helpers.h"                 // for GMockThrow
 #include "test_worker.h"                   // for TestFederated
 #include "xgboost/json.h"                  // for Json
 
@@ -20,19 +20,19 @@ class FederatedCommTest : public SocketTest {};
 
 TEST_F(FederatedCommTest, ThrowOnWorldSizeTooSmall) {
   auto construct = [] { FederatedComm comm{"localhost", 0, 0, 0}; };
-  ASSERT_THAT(construct,
-              ::testing::ThrowsMessage<dmlc::Error>(::testing::HasSubstr("Invalid world size")));
+  ASSERT_THAT(construct, GMockThrow("Invalid world size"));
 }
 
 TEST_F(FederatedCommTest, ThrowOnRankTooSmall) {
   auto construct = [] { FederatedComm comm{"localhost", 0, 1, -1}; };
-  ASSERT_THAT(construct,
-              ::testing::ThrowsMessage<dmlc::Error>(::testing::HasSubstr("Invalid worker rank.")));
+  ASSERT_THAT(construct, GMockThrow("Invalid worker rank."));
 }
 
 TEST_F(FederatedCommTest, ThrowOnRankTooBig) {
-  auto construct = [] { FederatedComm comm{"localhost", 0, 1, 1}; };
-  ExpectThrow<dmlc::Error>("Invalid worker rank.", construct);
+  auto construct = [] {
+    FederatedComm comm{"localhost", 0, 1, 1};
+  };
+  ASSERT_THAT(construct, GMockThrow("Invalid worker rank."));
 }
 
 TEST_F(FederatedCommTest, ThrowOnWorldSizeNotInteger) {
@@ -43,7 +43,7 @@ TEST_F(FederatedCommTest, ThrowOnWorldSizeNotInteger) {
     config["federated_rank"] = Integer(0);
     FederatedComm comm{DefaultRetry(), std::chrono::seconds{DefaultTimeoutSec()}, "", config};
   };
-  ExpectThrow<dmlc::Error>("got: `String`", construct);
+  ASSERT_THAT(construct, GMockThrow("got: `String`"));
 }
 
 TEST_F(FederatedCommTest, ThrowOnRankNotInteger) {
@@ -54,7 +54,7 @@ TEST_F(FederatedCommTest, ThrowOnRankNotInteger) {
     config["federated_rank"] = std::string("0");
     FederatedComm comm(DefaultRetry(), std::chrono::seconds{DefaultTimeoutSec()}, "", config);
   };
-  ExpectThrow<dmlc::Error>("got: `String`", construct);
+  ASSERT_THAT(construct, GMockThrow("got: `String`"));
 }
 
 TEST_F(FederatedCommTest, GetWorldSizeAndRank) {

tests/cpp/test_learner.cc

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2017-2023, XGBoost contributors
+ * Copyright 2017-2024, XGBoost contributors
  */
 #include <gtest/gtest.h>
 #include <gmock/gmock.h>
@@ -82,9 +82,7 @@ TEST(Learner, ParameterValidation) {
 
   // whitespace
   learner->SetParam("tree method", "exact");
-  EXPECT_THAT([&] { learner->Configure(); },
-              ::testing::ThrowsMessage<dmlc::Error>(
-                  ::testing::HasSubstr(R"("tree method" contains whitespace)")));
+  ASSERT_THAT([&] { learner->Configure(); }, GMockThrow(R"("tree method" contains whitespace)"));
 }
 
 TEST(Learner, CheckGroup) {