diff --git a/src/config.h b/src/config.h
--- a/src/config.h
+++ b/src/config.h
@@ -50,9 +50,8 @@
     explicit DummyConfig(std::string net);
     explicit DummyConfig(std::unique_ptr<CChainParams> chainParamsIn);
     bool SetMaxBlockSize(uint64_t maxBlockSize) override { return false; }
-    uint64_t GetMaxBlockSize() const override { return 0; }
+    uint64_t GetMaxBlockSize() const override { return 32'000'000; }
 
-    void SetChainParams(std::string net);
     const CChainParams &GetChainParams() const override { return *chainParams; }
 
     void SetCashAddrEncoding(bool) override {}
diff --git a/src/config.cpp b/src/config.cpp
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -50,7 +50,3 @@
 
 DummyConfig::DummyConfig(std::unique_ptr<CChainParams> chainParamsIn)
     : chainParams(std::move(chainParamsIn)) {}
-
-void DummyConfig::SetChainParams(std::string net) {
-    chainParams = CreateChainParams(net);
-}
diff --git a/src/test/checkpoints_tests.cpp b/src/test/checkpoints_tests.cpp
--- a/src/test/checkpoints_tests.cpp
+++ b/src/test/checkpoints_tests.cpp
@@ -24,9 +24,9 @@
 
 #include <memory>
 
-BOOST_FIXTURE_TEST_SUITE(checkpoints_tests, TestingSetup)
+BOOST_AUTO_TEST_SUITE(checkpoints_tests)
 
-BOOST_AUTO_TEST_CASE(sanity) {
+BOOST_FIXTURE_TEST_CASE(sanity, TestingSetup) {
     const auto params = CreateChainParams(CBaseChainParams::MAIN);
     const CCheckpointData &checkpoints = params->Checkpoints();
     BlockHash p11111 = BlockHash::fromHex(
@@ -70,6 +70,15 @@
     }
 };
 
+static const MainnetConfigWithTestCheckpoints g_config{};
+
+struct CheckpointsTestingSetup : public TestingSetup {
+    CheckpointsTestingSetup()
+        : TestingSetup{CBaseChainParams::MAIN, /*extra_args=*/{},
+                       /*coins_db_in_memory=*/true,
+                       /*block_tree_db_in_memory=*/true, g_config} {}
+};
+
 /**
  * This test has 4 precomputed blocks mined ontop of the genesis block:
  *  G ---> A ---> AA (checkpointed)
@@ -79,8 +88,11 @@
  *  * B should be rejected for forking prior to an accepted checkpoint
  *  * AB should be rejected for forking at an accepted checkpoint
  */
-BOOST_AUTO_TEST_CASE(ban_fork_prior_to_and_at_checkpoints) {
-    MainnetConfigWithTestCheckpoints config;
+BOOST_FIXTURE_TEST_CASE(ban_fork_prior_to_and_at_checkpoints,
+                        CheckpointsTestingSetup) {
+    const Config &config = m_node.chainman->GetConfig();
+    assert(std::addressof(config) == std::addressof(g_config));
+
     const CBlockIndex *pindex = nullptr;
 
     // Start with mainnet genesis block
diff --git a/src/test/util/setup_common.h b/src/test/util/setup_common.h
--- a/src/test/util/setup_common.h
+++ b/src/test/util/setup_common.h
@@ -7,6 +7,7 @@
 
 #include <blockindex.h>
 #include <chainparamsbase.h>
+#include <config.h>
 #include <consensus/amount.h>
 #include <fs.h>
 #include <key.h>
@@ -120,7 +121,8 @@
 
     explicit ChainTestingSetup(
         const std::string &chainName = CBaseChainParams::MAIN,
-        const std::vector<const char *> &extra_args = {});
+        const std::vector<const char *> &extra_args = {},
+        const Config &config = ::GetConfig());
     ~ChainTestingSetup();
 };
 
@@ -136,7 +138,8 @@
     explicit TestingSetup(const std::string &chainName = CBaseChainParams::MAIN,
                           const std::vector<const char *> &extra_args = {},
                           const bool coins_db_in_memory = true,
-                          const bool block_tree_db_in_memory = true);
+                          const bool block_tree_db_in_memory = true,
+                          const Config &config = ::GetConfig());
 };
 
 /** Identical to TestingSetup, but chain set to regtest */
diff --git a/src/test/util/setup_common.cpp b/src/test/util/setup_common.cpp
--- a/src/test/util/setup_common.cpp
+++ b/src/test/util/setup_common.cpp
@@ -194,10 +194,9 @@
 }
 
 ChainTestingSetup::ChainTestingSetup(
-    const std::string &chainName, const std::vector<const char *> &extra_args)
+    const std::string &chainName, const std::vector<const char *> &extra_args,
+    const Config &config)
     : BasicTestingSetup(chainName, extra_args) {
-    const Config &config = GetConfig();
-
     // We have to run a scheduler thread to prevent ActivateBestChain
     // from blocking due to queue overrun.
     m_node.scheduler = std::make_unique<CScheduler>();
@@ -273,12 +272,11 @@
 TestingSetup::TestingSetup(const std::string &chainName,
                            const std::vector<const char *> &extra_args,
                            const bool coins_db_in_memory,
-                           const bool block_tree_db_in_memory)
-    : ChainTestingSetup(chainName, extra_args),
+                           const bool block_tree_db_in_memory,
+                           const Config &config)
+    : ChainTestingSetup(chainName, extra_args, config),
       m_coins_db_in_memory(coins_db_in_memory),
       m_block_tree_db_in_memory(block_tree_db_in_memory) {
-    const Config &config = GetConfig();
-
     // Ideally we'd move all the RPC tests to the functional testing framework
     // instead of unit tests, but for now we need these here.
     RPCServer rpcServer;