CBD-6348: [BP] Fix problems with nlohmann and gtest

When building in C++20 mode there is some problems with the
version we have with gtest and nlohmann to implicit
conversion to the correct type.

Change-Id: Iad17e276b8fbc0b5945fabbe4acdd0e7619ce925
Reviewed-on: https://review.couchbase.org/c/kv_engine/+/234990
Well-Formed: Restriction Checker
Tested-by: Trond Norbye <[email protected]>
Reviewed-by: Mohammad Zaeem <[email protected]>

Author: trondn

tests/testapp/auth_provider_test.cc

@@ -82,7 +82,8 @@ TEST_F(AuthProviderTest, UnsupportedMech) {
             R"({"mechanism":"SCRAM-SHA1", "challenge":"foo", "authentication-only":false})");
     ASSERT_EQ(cb::mcbp::Status::NotSupported, ret.first);
     const auto json = nlohmann::json::parse(ret.second);
-    EXPECT_EQ("mechanism not supported", json["error"]["context"]);
+    EXPECT_EQ("mechanism not supported",
+              json["error"]["context"].get<std::string>());
 }
 
 TEST_F(AuthProviderTest, NoChallenge) {

tests/testapp/testapp_interfaces.cc

@@ -169,11 +169,11 @@ TEST_P(InterfacesTest, Prometheus) {
     EXPECT_TRUE(config["port"].is_number());
     EXPECT_LT(0, config["port"]);
     EXPECT_EQ("prometheus", config["type"]);
-    EXPECT_NE(uuid, config["uuid"]);
+    EXPECT_NE(uuid, config["uuid"].get<std::string>());
     uuid = config["uuid"];
 
     interfaces = getInterfaces(*adminConnection);
-    ASSERT_EQ(uuid, interfaces.back()["uuid"])
+    ASSERT_EQ(uuid, interfaces.back()["uuid"].get<std::string>())
             << "list interfaces should return the newly created interface";
 }
 
@@ -329,7 +329,7 @@ TEST_P(InterfacesTest, TlsPropertiesEncryptedKey) {
     ASSERT_TRUE(rsp.isSuccess()) << to_string(rsp.getStatus()) << std::endl
                                  << rsp.getDataString();
     auto json = rsp.getDataJson();
-    EXPECT_EQ("set", json["password"]) << json.dump(2);
+    EXPECT_EQ("set", json["password"].get<std::string>()) << json.dump(2);
 }
 
 TEST_P(InterfacesTest, TlsPropertiesEncryptedCertInvalidPassphrase) {

tests/testapp/testapp_rbac.cc

@@ -134,7 +134,7 @@ TEST_P(RbacTest, MB23909_ErrorIncudingErrorInfo) {
     const std::string expected{
             "Authorization failure: can't execute RBAC_REFRESH operation "
             "without the SecurityManagement privilege"};
-    EXPECT_EQ(expected, json["error"]["context"]);
+    EXPECT_EQ(expected, json["error"]["context"].get<std::string>());
 }
 
 class RbacRoleTest : public TestappClientTest {