1 files changed, 95 insertions, 0 deletions
diff --git a/resolv/res_cache_test.cpp b/resolv/res_cache_test.cpp
new file mode 100644
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--- /dev/null
+++ b/resolv/res_cache_test.cpp
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#include <netdb.h>
+
+#include <cutils/properties.h>
+#include <gmock/gmock-matchers.h>
+#include <gtest/gtest.h>
+
+#include "netd_resolv/stats.h"
+#include "resolv_cache.h"
+
+constexpr int TEST_NETID = 30;
+
+namespace {
+
+constexpr int EAI_OK = 0;
+constexpr char DNS_EVENT_SUBSAMPLING_MAP_FLAG[] =
+        "persist.device_config.netd_native.dns_event_subsample_map";
+
+class ScopedCacheCreate {
+  public:
+    explicit ScopedCacheCreate(unsigned netid, const char* subsampling_map,
+                               const char* property = DNS_EVENT_SUBSAMPLING_MAP_FLAG)
+        : mStoredNetId(netid), mStoredProperty(property) {
+        property_get(property, mStoredMap, "");
+        property_set(property, subsampling_map);
+        EXPECT_EQ(0, resolv_create_cache_for_net(netid));
+    }
+    ~ScopedCacheCreate() {
+        resolv_delete_cache_for_net(mStoredNetId);
+        property_set(mStoredProperty, mStoredMap);
+    }
+
+  private:
+    unsigned mStoredNetId;
+    const char* mStoredProperty;
+    char mStoredMap[PROPERTY_VALUE_MAX]{};
+};
+
+}  // namespace
+
+TEST(ResolvCacheTest, DnsEventSubsampling) {
+    // Test defaults, default flag is "default:1 0:100 7:10" if no experiment flag is set
+    {
+        ScopedCacheCreate scopedCacheCreate(TEST_NETID, "");
+        EXPECT_EQ(resolv_cache_get_subsampling_denom(TEST_NETID, EAI_NODATA), 10U);
+        EXPECT_EQ(resolv_cache_get_subsampling_denom(TEST_NETID, EAI_OK), 100U);
+        EXPECT_EQ(resolv_cache_get_subsampling_denom(TEST_NETID, EAI_BADFLAGS),
+                  1U);  // default
+        EXPECT_THAT(resolv_cache_dump_subsampling_map(TEST_NETID),
+                    testing::UnorderedElementsAreArray({"default:1", "0:100", "7:10"}));
+    }
+    // Now change the experiment flag to "0:42 default:666"
+    {
+        ScopedCacheCreate scopedCacheCreate(TEST_NETID, "0:42 default:666");
+        EXPECT_EQ(resolv_cache_get_subsampling_denom(TEST_NETID, EAI_OK), 42U);
+        EXPECT_EQ(resolv_cache_get_subsampling_denom(TEST_NETID, EAI_NODATA),
+                  666U);  // default
+        EXPECT_THAT(resolv_cache_dump_subsampling_map(TEST_NETID),
+                    testing::UnorderedElementsAreArray({"default:666", "0:42"}));
+    }
+    // Now change the experiment flag to something illegal
+    {
+        ScopedCacheCreate scopedCacheCreate(TEST_NETID, "asvaxx");
+        // 0(disable log) is the default value if experiment flag is invalid.
+        EXPECT_EQ(resolv_cache_get_subsampling_denom(TEST_NETID, EAI_OK), 0U);
+        EXPECT_EQ(resolv_cache_get_subsampling_denom(TEST_NETID, EAI_NODATA), 0U);
+        EXPECT_TRUE(resolv_cache_dump_subsampling_map(TEST_NETID).empty());
+    }
+    // Test negative and zero denom
+    {
+        ScopedCacheCreate scopedCacheCreate(TEST_NETID, "0:-42 default:-666 7:10 10:0");
+        // 0(disable log) is the default value if no valid denom is set
+        EXPECT_EQ(resolv_cache_get_subsampling_denom(TEST_NETID, EAI_OK), 0U);
+        EXPECT_EQ(resolv_cache_get_subsampling_denom(TEST_NETID, EAI_BADFLAGS), 0U);
+        EXPECT_EQ(resolv_cache_get_subsampling_denom(TEST_NETID, EAI_NODATA), 10U);
+        EXPECT_EQ(resolv_cache_get_subsampling_denom(TEST_NETID, EAI_SOCKTYPE), 0U);
+        EXPECT_THAT(resolv_cache_dump_subsampling_map(TEST_NETID),
+                    testing::UnorderedElementsAreArray({"7:10", "10:0"}));
+    }
+}