diff --git a/streamingvisitors/src/tests/docsum/CMakeLists.txt b/streamingvisitors/src/tests/docsum/CMakeLists.txt
index 15c1e26b08b0..4634a8c60b07 100644
--- a/streamingvisitors/src/tests/docsum/CMakeLists.txt
+++ b/streamingvisitors/src/tests/docsum/CMakeLists.txt
@@ -4,5 +4,6 @@ vespa_add_executable(vsm_docsum_test_app TEST
     docsum_test.cpp
     DEPENDS
     streamingvisitors
+    GTest::gtest
 )
 vespa_add_test(NAME vsm_docsum_test_app COMMAND vsm_docsum_test_app)
diff --git a/streamingvisitors/src/tests/docsum/docsum_test.cpp b/streamingvisitors/src/tests/docsum/docsum_test.cpp
index d6535046e876..112a4e7f6796 100644
--- a/streamingvisitors/src/tests/docsum/docsum_test.cpp
+++ b/streamingvisitors/src/tests/docsum/docsum_test.cpp
@@ -1,5 +1,5 @@
 // Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-#include <vespa/vespalib/testkit/testapp.h>
+
 #include <vespa/document/fieldvalue/fieldvalues.h>
 #include <vespa/document/datatype/structdatatype.h>
 #include <vespa/document/datatype/weightedsetdatatype.h>
@@ -9,6 +9,7 @@
 #include <vespa/vsm/vsm/flattendocsumwriter.h>
 #include <vespa/vespalib/data/smart_buffer.h>
 #include <vespa/vespalib/data/slime/slime.h>
+#include <vespa/vespalib/gtest/gtest.h>
 
 using namespace document;
 
@@ -48,24 +49,29 @@ class TestDocument : public vsm::Document
 };
 
 
-class DocsumTest : public vespalib::TestApp
+class DocsumTest : public ::testing::Test
 {
-private:
+protected:
     ArrayFieldValue createFieldValue(const StringList & fv);
     WeightedSetFieldValue createFieldValue(const WeightedStringList & fv);
 
-    void assertFlattenDocsumWriter(const FieldValue & fv, const std::string & exp) {
+    void assertFlattenDocsumWriter(const FieldValue & fv, const std::string & exp, const std::string& label) {
         FlattenDocsumWriter fdw;
-        assertFlattenDocsumWriter(fdw, fv, exp);
+        assertFlattenDocsumWriter(fdw, fv, exp, label);
     }
-    void assertFlattenDocsumWriter(FlattenDocsumWriter & fdw, const FieldValue & fv, const std::string & exp);
-    void testFlattenDocsumWriter();
-    void testDocSumCache();
+    void assertFlattenDocsumWriter(FlattenDocsumWriter & fdw, const FieldValue & fv, const std::string & exp, const std::string& label);
 
-public:
-    int Main() override;
+    DocsumTest();
+    ~DocsumTest() override;
 };
 
+DocsumTest::DocsumTest()
+    : ::testing::Test()
+{
+}
+
+DocsumTest::~DocsumTest() = default;
+
 ArrayFieldValue
 DocsumTest::createFieldValue(const StringList & fv)
 {
@@ -90,62 +96,54 @@ DocsumTest::createFieldValue(const WeightedStringList & fv)
 }
 
 void
-DocsumTest::assertFlattenDocsumWriter(FlattenDocsumWriter & fdw, const FieldValue & fv, const std::string & exp)
+DocsumTest::assertFlattenDocsumWriter(FlattenDocsumWriter & fdw, const FieldValue & fv, const std::string & exp, const std::string& label)
 {
+    SCOPED_TRACE(label);
     FieldPath empty;
     fv.iterateNested(empty.getFullRange(), fdw);
     std::string actual(fdw.getResult().getBuffer(), fdw.getResult().getPos());
-    EXPECT_EQUAL(actual, exp);
+    EXPECT_EQ(exp, actual);
 }
 
-void
-DocsumTest::testFlattenDocsumWriter()
+TEST_F(DocsumTest, flatten_docsum_writer_basic)
 {
-    { // basic tests
-        TEST_DO(assertFlattenDocsumWriter(StringFieldValue("foo bar"), "foo bar"));
-        TEST_DO(assertFlattenDocsumWriter(RawFieldValue("foo bar"), "foo bar"));
-        TEST_DO(assertFlattenDocsumWriter(BoolFieldValue(true), "true"));
-        TEST_DO(assertFlattenDocsumWriter(BoolFieldValue(false), "false"));
-        TEST_DO(assertFlattenDocsumWriter(LongFieldValue(123456789), "123456789"));
-        TEST_DO(assertFlattenDocsumWriter(createFieldValue(StringList().add("foo bar").add("baz").add(" qux ")),
-                                  "foo bar baz  qux "));
-    }
-    { // test mulitple invocations
-        FlattenDocsumWriter fdw("#");
-        TEST_DO(assertFlattenDocsumWriter(fdw, StringFieldValue("foo"), "foo"));
-        TEST_DO(assertFlattenDocsumWriter(fdw, StringFieldValue("bar"), "foo#bar"));
-        fdw.clear();
-        TEST_DO(assertFlattenDocsumWriter(fdw, StringFieldValue("baz"), "baz"));
-        TEST_DO(assertFlattenDocsumWriter(fdw, StringFieldValue("qux"), "baz qux"));
-    }
-    { // test resizing
-        FlattenDocsumWriter fdw("#");
-        EXPECT_EQUAL(fdw.getResult().getPos(), 0u);
-        EXPECT_EQUAL(fdw.getResult().getLength(), 32u);
-        TEST_DO(assertFlattenDocsumWriter(fdw, StringFieldValue("aaaabbbbccccddddeeeeffffgggghhhh"),
-                                          "aaaabbbbccccddddeeeeffffgggghhhh"));
-        EXPECT_EQUAL(fdw.getResult().getPos(), 32u);
-        EXPECT_EQUAL(fdw.getResult().getLength(), 32u);
-        TEST_DO(assertFlattenDocsumWriter(fdw, StringFieldValue("aaaa"), "aaaabbbbccccddddeeeeffffgggghhhh#aaaa"));
-        EXPECT_EQUAL(fdw.getResult().getPos(), 37u);
-        EXPECT_TRUE(fdw.getResult().getLength() >= 37u);
-        fdw.clear();
-        EXPECT_EQUAL(fdw.getResult().getPos(), 0u);
-        EXPECT_TRUE(fdw.getResult().getLength() >= 37u);
-    }
+    assertFlattenDocsumWriter(StringFieldValue("foo bar"), "foo bar", "string foo bar");
+    assertFlattenDocsumWriter(RawFieldValue("foo bar"), "foo bar", "raw foo bar");
+    assertFlattenDocsumWriter(BoolFieldValue(true), "true", "bool true");
+    assertFlattenDocsumWriter(BoolFieldValue(false), "false", "bool false");
+    assertFlattenDocsumWriter(LongFieldValue(123456789), "123456789", "long");
+    assertFlattenDocsumWriter(createFieldValue(StringList().add("foo bar").add("baz").add(" qux ")),
+                                               "foo bar baz  qux ", "wset");
 }
 
-int
-DocsumTest::Main()
+TEST_F(DocsumTest, flatten_docsum_writer_multiple_invocations)
 {
-    TEST_INIT("docsum_test");
-
-    TEST_DO(testFlattenDocsumWriter());
-
-    TEST_DONE();
+    FlattenDocsumWriter fdw("#");
+    assertFlattenDocsumWriter(fdw, StringFieldValue("foo"), "foo", "string foo");
+    assertFlattenDocsumWriter(fdw, StringFieldValue("bar"), "foo#bar", "string bar");
+    fdw.clear();
+    assertFlattenDocsumWriter(fdw, StringFieldValue("baz"), "baz", "string baz");
+    assertFlattenDocsumWriter(fdw, StringFieldValue("qux"), "baz qux", "string qux");
 }
 
+TEST_F(DocsumTest, flatten_docsum_writer_resizing)
+{
+    FlattenDocsumWriter fdw("#");
+    EXPECT_EQ(fdw.getResult().getPos(), 0u);
+    EXPECT_EQ(fdw.getResult().getLength(), 32u);
+    assertFlattenDocsumWriter(fdw, StringFieldValue("aaaabbbbccccddddeeeeffffgggghhhh"),
+                              "aaaabbbbccccddddeeeeffffgggghhhh",
+                              "string long");
+    EXPECT_EQ(fdw.getResult().getPos(), 32u);
+    EXPECT_EQ(fdw.getResult().getLength(), 32u);
+    assertFlattenDocsumWriter(fdw, StringFieldValue("aaaa"), "aaaabbbbccccddddeeeeffffgggghhhh#aaaa", "string second long");
+    EXPECT_EQ(fdw.getResult().getPos(), 37u);
+    EXPECT_TRUE(fdw.getResult().getLength() >= 37u);
+    fdw.clear();
+    EXPECT_EQ(fdw.getResult().getPos(), 0u);
+    EXPECT_TRUE(fdw.getResult().getLength() >= 37u);
 }
 
-TEST_APPHOOK(vsm::DocsumTest);
+}
 
+GTEST_MAIN_RUN_ALL_TESTS()