diff --git a/tests/qapi-schema/qapi-schema-test.json b/tests/qapi-schema/qapi-schema-test.json
index 3f62821..8405021 100644
--- a/tests/qapi-schema/qapi-schema-test.json
+++ b/tests/qapi-schema/qapi-schema-test.json
@@ -32,6 +32,10 @@
 { 'union': 'UserDefUnion',
   'data': { 'a' : 'UserDefA', 'b' : 'UserDefB' } }
 
+{ 'union': 'UserDefAnonUnion',
+  'discriminator': {},
+  'data': { 'uda': 'UserDefA', 's': 'str', 'i': 'int' } }
+
 # for testing native lists
 { 'union': 'UserDefNativeListUnion',
   'data': { 'integer': ['int'],
diff --git a/tests/qapi-schema/qapi-schema-test.out b/tests/qapi-schema/qapi-schema-test.out
index 59468ac..ac98f32 100644
--- a/tests/qapi-schema/qapi-schema-test.out
+++ b/tests/qapi-schema/qapi-schema-test.out
@@ -6,13 +6,17 @@
  OrderedDict([('type', 'UserDefA'), ('data', OrderedDict([('boolean', 'bool')]))]),
  OrderedDict([('type', 'UserDefB'), ('data', OrderedDict([('integer', 'int')]))]),
  OrderedDict([('union', 'UserDefUnion'), ('data', OrderedDict([('a', 'UserDefA'), ('b', 'UserDefB')]))]),
+ OrderedDict([('union', 'UserDefAnonUnion'), ('discriminator', OrderedDict()), ('data', OrderedDict([('uda', 'UserDefA'), ('s', 'str'), ('i', 'int')]))]),
  OrderedDict([('union', 'UserDefNativeListUnion'), ('data', OrderedDict([('integer', ['int']), ('s8', ['int8']), ('s16', ['int16']), ('s32', ['int32']), ('s64', ['int64']), ('u8', ['uint8']), ('u16', ['uint16']), ('u32', ['uint32']), ('u64', ['uint64']), ('number', ['number']), ('boolean', ['bool']), ('string', ['str'])]))]),
  OrderedDict([('command', 'user_def_cmd'), ('data', OrderedDict())]),
  OrderedDict([('command', 'user_def_cmd1'), ('data', OrderedDict([('ud1a', 'UserDefOne')]))]),
  OrderedDict([('command', 'user_def_cmd2'), ('data', OrderedDict([('ud1a', 'UserDefOne'), ('*ud1b', 'UserDefOne')])), ('returns', 'UserDefTwo')]),
  OrderedDict([('command', 'user_def_cmd3'), ('data', OrderedDict([('a', 'int'), ('*b', 'int')])), ('returns', 'int')]),
  OrderedDict([('type', 'UserDefOptions'), ('data', OrderedDict([('*i64', ['int']), ('*u64', ['uint64']), ('*u16', ['uint16']), ('*i64x', 'int'), ('*u64x', 'uint64')]))])]
-['EnumOne', 'UserDefUnionKind', 'UserDefNativeListUnionKind']
+['EnumOne',
+ 'UserDefUnionKind',
+ 'UserDefAnonUnionKind',
+ 'UserDefNativeListUnionKind']
 [OrderedDict([('type', 'NestedEnumsOne'), ('data', OrderedDict([('enum1', 'EnumOne'), ('*enum2', 'EnumOne'), ('enum3', 'EnumOne'), ('*enum4', 'EnumOne')]))]),
  OrderedDict([('type', 'UserDefOne'), ('data', OrderedDict([('integer', 'int'), ('string', 'str'), ('*enum1', 'EnumOne')]))]),
  OrderedDict([('type', 'UserDefTwo'), ('data', OrderedDict([('string', 'str'), ('dict', OrderedDict([('string', 'str'), ('dict', OrderedDict([('userdef', 'UserDefOne'), ('string', 'str')])), ('*dict2', OrderedDict([('userdef', 'UserDefOne'), ('string', 'str')]))]))]))]),
diff --git a/tests/test-qmp-input-strict.c b/tests/test-qmp-input-strict.c
index 38bdf5e..67adc2a 100644
--- a/tests/test-qmp-input-strict.c
+++ b/tests/test-qmp-input-strict.c
@@ -139,6 +139,20 @@ static void test_validate_union(TestInputVisitorData *data,
     qapi_free_UserDefUnion(tmp);
 }
 
+static void test_validate_union_anon(TestInputVisitorData *data,
+                                     const void *unused)
+{
+    UserDefAnonUnion *tmp = NULL;
+    Visitor *v;
+    Error *errp = NULL;
+
+    v = validate_test_init(data, "42");
+
+    visit_type_UserDefAnonUnion(v, &tmp, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    qapi_free_UserDefAnonUnion(tmp);
+}
+
 static void test_validate_fail_struct(TestInputVisitorData *data,
                                        const void *unused)
 {
@@ -198,6 +212,20 @@ static void test_validate_fail_union(TestInputVisitorData *data,
     qapi_free_UserDefUnion(tmp);
 }
 
+static void test_validate_fail_union_anon(TestInputVisitorData *data,
+                                          const void *unused)
+{
+    UserDefAnonUnion *tmp = NULL;
+    Visitor *v;
+    Error *errp = NULL;
+
+    v = validate_test_init(data, "3.14");
+
+    visit_type_UserDefAnonUnion(v, &tmp, NULL, &errp);
+    g_assert(error_is_set(&errp));
+    qapi_free_UserDefAnonUnion(tmp);
+}
+
 static void validate_test_add(const char *testpath,
                                TestInputVisitorData *data,
                                void (*test_func)(TestInputVisitorData *data, const void *user_data))
@@ -220,6 +248,8 @@ int main(int argc, char **argv)
                        &testdata, test_validate_list);
     validate_test_add("/visitor/input-strict/pass/union",
                        &testdata, test_validate_union);
+    validate_test_add("/visitor/input-strict/pass/union-anon",
+                       &testdata, test_validate_union_anon);
     validate_test_add("/visitor/input-strict/fail/struct",
                        &testdata, test_validate_fail_struct);
     validate_test_add("/visitor/input-strict/fail/struct-nested",
@@ -228,6 +258,8 @@ int main(int argc, char **argv)
                        &testdata, test_validate_fail_list);
     validate_test_add("/visitor/input-strict/fail/union",
                        &testdata, test_validate_fail_union);
+    validate_test_add("/visitor/input-strict/fail/union-anon",
+                       &testdata, test_validate_fail_union_anon);
 
     g_test_run();
 
diff --git a/tests/test-qmp-input-visitor.c b/tests/test-qmp-input-visitor.c
index 6eb7dc5..eadb6e9 100644
--- a/tests/test-qmp-input-visitor.c
+++ b/tests/test-qmp-input-visitor.c
@@ -302,6 +302,22 @@ static void test_visitor_in_union(TestInputVisitorData *data,
     qapi_free_UserDefUnion(tmp);
 }
 
+static void test_visitor_in_union_anon(TestInputVisitorData *data,
+                                       const void *unused)
+{
+    Visitor *v;
+    Error *err = NULL;
+    UserDefAnonUnion *tmp;
+
+    v = visitor_input_test_init(data, "42");
+
+    visit_type_UserDefAnonUnion(v, &tmp, NULL, &err);
+    g_assert(err == NULL);
+    g_assert_cmpint(tmp->kind, ==, USER_DEF_ANON_UNION_KIND_I);
+    g_assert_cmpint(tmp->i, ==, 42);
+    qapi_free_UserDefAnonUnion(tmp);
+}
+
 static void test_native_list_integer_helper(TestInputVisitorData *data,
                                             const void *unused,
                                             UserDefNativeListUnionKind kind)
@@ -635,6 +651,8 @@ int main(int argc, char **argv)
                             &in_visitor_data, test_visitor_in_list);
     input_visitor_test_add("/visitor/input/union",
                             &in_visitor_data, test_visitor_in_union);
+    input_visitor_test_add("/visitor/input/union-anon",
+                            &in_visitor_data, test_visitor_in_union_anon);
     input_visitor_test_add("/visitor/input/errors",
                             &in_visitor_data, test_visitor_in_errors);
     input_visitor_test_add("/visitor/input/native_list/int",
diff --git a/tests/test-qmp-output-visitor.c b/tests/test-qmp-output-visitor.c
index f31d168..ae4e68c 100644
--- a/tests/test-qmp-output-visitor.c
+++ b/tests/test-qmp-output-visitor.c
@@ -434,6 +434,26 @@ static void test_visitor_out_union(TestOutputVisitorData *data,
     QDECREF(qdict);
 }
 
+static void test_visitor_out_union_anon(TestOutputVisitorData *data,
+                                        const void *unused)
+{
+    QObject *arg;
+    Error *err = NULL;
+
+    UserDefAnonUnion *tmp = g_malloc0(sizeof(UserDefAnonUnion));
+    tmp->kind = USER_DEF_ANON_UNION_KIND_I;
+    tmp->i = 42;
+
+    visit_type_UserDefAnonUnion(data->ov, &tmp, NULL, &err);
+    g_assert(err == NULL);
+    arg = qmp_output_get_qobject(data->qov);
+
+    g_assert(qobject_type(arg) == QTYPE_QINT);
+    g_assert_cmpint(qint_get_int(qobject_to_qint(arg)), ==, 42);
+
+    qapi_free_UserDefAnonUnion(tmp);
+}
+
 static void init_native_list(UserDefNativeListUnion *cvalue)
 {
     int i;
@@ -782,6 +802,8 @@ int main(int argc, char **argv)
                             &out_visitor_data, test_visitor_out_list_qapi_free);
     output_visitor_test_add("/visitor/output/union",
                             &out_visitor_data, test_visitor_out_union);
+    output_visitor_test_add("/visitor/output/union-anon",
+                            &out_visitor_data, test_visitor_out_union_anon);
     output_visitor_test_add("/visitor/output/native_list/int",
                             &out_visitor_data, test_visitor_out_native_list_int);
     output_visitor_test_add("/visitor/output/native_list/int8",
