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diff --git a/src/mongo/db/ftdc/varint_test.cpp b/src/mongo/db/ftdc/varint_test.cpp
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+++ b/src/mongo/db/ftdc/varint_test.cpp
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+/**
+ * Copyright (C) 2015 MongoDB Inc.
+ *
+ * This program is free software: you can redistribute it and/or  modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * As a special exception, the copyright holders give permission to link the
+ * code of portions of this program with the OpenSSL library under certain
+ * conditions as described in each individual source file and distribute
+ * linked combinations including the program with the OpenSSL library. You
+ * must comply with the GNU Affero General Public License in all respects
+ * for all of the code used other than as permitted herein. If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so. If you do not
+ * wish to do so, delete this exception statement from your version. If you
+ * delete this exception statement from all source files in the program,
+ * then also delete it in the license file.
+ */
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/base/data_builder.h"
+#include "mongo/base/data_type_validated.h"
+#include "mongo/base/init.h"
+#include "mongo/db/client.h"
+#include "mongo/db/ftdc/collector.h"
+#include "mongo/db/ftdc/config.h"
+#include "mongo/db/ftdc/controller.h"
+#include "mongo/db/ftdc/varint.h"
+#include "mongo/unittest/unittest.h"
+
+namespace mongo {
+
+// Test integer packing and unpacking
+void TestInt(std::uint64_t i) {
+    char buf[11];
+
+    DataView dvWrite(&buf[0]);
+
+    dvWrite.write(i);
+
+    ConstDataView cdvRead(&buf[0]);
+
+    std::uint64_t d = cdvRead.read<std::uint64_t>();
+
+    ASSERT_EQUALS(i, d);
+}
+
+// Test various integer combinations compress and uncompress correctly
+TEST(FTDCVarIntTest, TestIntCompression) {
+    // Check numbers with leading 1
+    for (int i = 0; i < 63; i++) {
+        TestInt(i);
+        TestInt(i - 1);
+    }
+
+    // Check numbers composed of repeating hex numbers
+    for (int i = 0; i < 15; i++) {
+        int v = 0;
+        for (int j = 0; j < 15; j++) {
+            v = v << 4 | i;
+            TestInt(v);
+        }
+    }
+}
+
+// Test data builder can write a lot of zeros
+TEST(FTDCVarIntTest, TestDataBuilder) {
+    DataBuilder db(1);
+
+    // DataBuilder grows by 2x, and we reserve 10 bytes
+    // lcm(2**x, 10) == 16
+    for (int i = 0; i < 16; i++) {
+        auto s1 = db.writeAndAdvance(FTDCVarInt(0));
+        ASSERT_OK(s1);
+    };
+}
+
+}  // namespace mongo