@@ -175,3 +175,114 @@ where
             })
         })
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::rpc::core::MockCoreRPCLike;
+    use crate::test::helpers::setup::TestPlatformBuilder;
+
+    /// Exercises the early-return path in `check_tx` where `r#type.try_into()?`
+    /// propagates a `BadRequest` error before the validation result pipeline is
+    /// reached. Unlike the `.or_else` branch which converts errors into responses,
+    /// this error path propagates out of the handler entirely.
+    #[test]
+    fn check_tx_invalid_check_tx_type_propagates_bad_request_error() {
+        let platform = TestPlatformBuilder::new()
+            .with_latest_protocol_version()
+            .build_with_mock_rpc()
+            .set_initial_state_structure();
+        let core_rpc = MockCoreRPCLike::new();
+
+        let request = proto::RequestCheckTx {
+            tx: vec![1, 2, 3],
+            // Only 0 (New) and 1 (Recheck) are valid. 2 is rejected by TryFrom.
+            r#type: 2,
+        };
+
+        let result = check_tx(&platform.platform, &core_rpc, request);
+
+        assert!(result.is_err());
+        let err = result.unwrap_err();
+        let err_str = err.to_string();
+        assert!(
+            err_str.contains("CheckTxLevel") || err_str.contains("2"),
+            "expected BadRequest about CheckTxLevel, got: {}",
+            err_str
+        );
+    }
+
+    /// Exercises the error-path of the main `and_then` branch where the
+    /// `check_tx_v0` code produces a `ValidationResult` with a consensus error
+    /// (`InvalidEncoding` from `decode_raw_state_transitions`) for garbage bytes.
+    /// Covers the code/info propagation via `response_info_for_version`.
+    #[test]
+    fn check_tx_garbage_bytes_returns_nonzero_consensus_code() {
+        let platform = TestPlatformBuilder::new()
+            .with_latest_protocol_version()
+            .build_with_mock_rpc()
+            .set_initial_state_structure();
+        let core_rpc = MockCoreRPCLike::new();
+
+        // Random garbage is guaranteed to fail state transition deserialization.
+        let request = proto::RequestCheckTx {
+            tx: vec![0xFF, 0xFE, 0xFD, 0xFC, 0xFB, 0xFA],
+            r#type: 0,
+        };
+
+        let response = check_tx(&platform.platform, &core_rpc, request)
+            .expect("handler should return Ok with a consensus error code in the response");
+
+        // Rejected, non-zero code and non-empty info (base64-encoded consensus info).
+        assert_ne!(response.code, 0);
+        assert!(
+            !response.info.is_empty(),
+            "expected non-empty response info for consensus error"
+        );
+        assert_eq!(response.gas_wanted, 0);
+    }
+
+    /// Recheck mode (type = 1) should take the same code paths as new, but with
+    /// the different label; here we confirm the handler also returns a response
+    /// (not an error) for garbage bytes in Recheck mode.
+    #[test]
+    fn check_tx_garbage_bytes_recheck_returns_response() {
+        let platform = TestPlatformBuilder::new()
+            .with_latest_protocol_version()
+            .build_with_mock_rpc()
+            .set_initial_state_structure();
+        let core_rpc = MockCoreRPCLike::new();
+
+        let request = proto::RequestCheckTx {
+            tx: vec![0x00, 0x01, 0x02, 0x03],
+            r#type: 1, // Recheck
+        };
+
+        let response = check_tx(&platform.platform, &core_rpc, request)
+            .expect("recheck with garbage bytes should not produce an Err");
+
+        assert_ne!(response.code, 0);
+    }
+
+    /// An empty body is a boundary case: depending on decoding, it produces an
+    /// `InvalidEncoding` error. The handler should still return Ok with a
+    /// rejection code - not propagate an error.
+    #[test]
+    fn check_tx_empty_tx_body_returns_rejection_code() {
+        let platform = TestPlatformBuilder::new()
+            .with_latest_protocol_version()
+            .build_with_mock_rpc()
+            .set_initial_state_structure();
+        let core_rpc = MockCoreRPCLike::new();
+
+        let request = proto::RequestCheckTx {
+            tx: vec![],
+            r#type: 0,
+        };
+
+        let response = check_tx(&platform.platform, &core_rpc, request)
+            .expect("empty tx should not propagate an Err");
+
+        assert_ne!(response.code, 0);
+    }
+}
@@ -917,6 +917,10 @@ impl Default for PlatformTestConfig {
 #[cfg(test)]
 mod tests {
     use super::FromEnv;
+    use crate::config::{
+        ChainLockConfig, ConsensusCoreRpcConfig, CoreConfig, InstantLockConfig, PlatformConfig,
+        QuorumLikeConfig, ValidatorSetConfig,
+    };
     use crate::logging::LogDestination;
     use dpp::dashcore::Network;
     use dpp::dashcore_rpc::dashcore_rpc_json::QuorumType;
@@ -969,4 +973,265 @@ mod tests {
         assert_eq!(config.network, config.drive.network);
         assert_eq!(config.network, Network::Testnet);
     }
+
+    // --- `from_str_to_network_with_aliases`: valid aliases and error path ---
+
+    /// Ensures every network alias accepted by the deserializer maps to the
+    /// expected `Network`, case-insensitively. This exercises each match arm in
+    /// `from_str_to_network_with_aliases`, which is otherwise only called at
+    /// most once per integration-test setup.
+    #[test]
+    fn network_aliases_deserialize_all_variants_case_insensitively() {
+        let cases = &[
+            ("\"dash\"", Network::Mainnet),
+            ("\"DASH\"", Network::Mainnet),
+            ("\"MainNet\"", Network::Mainnet),
+            ("\"main\"", Network::Mainnet),
+            ("\"local\"", Network::Regtest),
+            ("\"regtest\"", Network::Regtest),
+            ("\"testnet\"", Network::Testnet),
+            ("\"TEST\"", Network::Testnet),
+            ("\"devnet\"", Network::Devnet),
+            ("\"Dev\"", Network::Devnet),
+        ];
+
+        for (input, expected) in cases {
+            let mut de = serde_json::Deserializer::from_str(input);
+            let network = super::from_str_to_network_with_aliases(&mut de)
+                .expect("alias should parse successfully");
+            assert_eq!(
+                &network, expected,
+                "input {} should map to {:?}",
+                input, expected
+            );
+        }
+    }
+
+    /// Verifies that an unknown network alias produces a clear deserializer error.
+    /// This covers the final arm of `from_str_to_network_with_aliases`.
+    #[test]
+    fn network_alias_unknown_value_returns_custom_error() {
+        let mut de = serde_json::Deserializer::from_str("\"nonsense_network\"");
+        let err = super::from_str_to_network_with_aliases(&mut de)
+            .expect_err("unknown network should fail");
+        let msg = err.to_string();
+        assert!(
+            msg.contains("unknown network") && msg.contains("nonsense_network"),
+            "error message should name the offending value, got: {}",
+            msg
+        );
+    }
+
+    // --- `deserialize_quorum_type`: numeric/string/UNKNOWN error path ---
+
+    /// Covers the string-name branch of `deserialize_quorum_type`.
+    #[test]
+    fn deserialize_quorum_type_accepts_string_names() {
+        // All numeric fields use `from_str_or_number`, which requires a JSON
+        // string (even for numbers).
+        let json = r#"{
+            "validator_set_quorum_type": "llmq_25_67",
+            "validator_set_quorum_size": "25",
+            "validator_set_quorum_window": "24",
+            "validator_set_quorum_active_signers": "24",
+            "validator_set_quorum_rotation": "false"
+        }"#;
+        let cfg: ValidatorSetConfig =
+            serde_json::from_str(json).expect("quorum type string should deserialize");
+        assert_eq!(cfg.quorum_type, QuorumType::Llmq25_67);
+    }
+
+    /// Covers the numeric (u32) branch of `deserialize_quorum_type` (a number
+    /// serialized as a JSON string still goes through the `parse::<u32>()` path).
+    #[test]
+    fn deserialize_quorum_type_accepts_numeric_string() {
+        let json = r#"{
+            "validator_set_quorum_type": "6",
+            "validator_set_quorum_size": "25",
+            "validator_set_quorum_window": "24",
+            "validator_set_quorum_active_signers": "24",
+            "validator_set_quorum_rotation": "false"
+        }"#;
+        let cfg: ValidatorSetConfig =
+            serde_json::from_str(json).expect("numeric quorum type should deserialize");
+        // QuorumType::from(6) should be a known variant; we only assert it is not UNKNOWN.
+        assert_ne!(cfg.quorum_type, QuorumType::UNKNOWN);
+    }
+
+    /// Covers the `UNKNOWN` rejection branch of `deserialize_quorum_type`.
+    #[test]
+    fn deserialize_quorum_type_rejects_unknown_names() {
+        let json = r#"{
+            "validator_set_quorum_type": "this_is_not_a_quorum",
+            "validator_set_quorum_size": "25",
+            "validator_set_quorum_window": "24",
+            "validator_set_quorum_active_signers": "24",
+            "validator_set_quorum_rotation": "false"
+        }"#;
+        let err = serde_json::from_str::<ValidatorSetConfig>(json)
+            .expect_err("unknown quorum type name should fail");
+        let msg = err.to_string();
+        assert!(
+            msg.contains("unsupported") && msg.contains("QUORUM_TYPE"),
+            "expected unsupported QUORUM_TYPE error, got: {}",
+            msg
+        );
+    }
+
+    // --- Core RPC URL composition and defaults ---
+
+    /// Exercises `ConsensusCoreRpcConfig::url` formatting.
+    #[test]
+    fn consensus_core_rpc_url_composes_host_and_port() {
+        let cfg = ConsensusCoreRpcConfig {
+            host: "node.example".to_string(),
+            port: 9998,
+            username: "u".to_string(),
+            password: "p".to_string(),
+        };
+        assert_eq!(cfg.url(), "node.example:9998");
+    }
+
+    /// Exercises `CheckTxCoreRpcConfig::url` formatting.
+    #[test]
+    fn check_tx_core_rpc_url_composes_host_and_port() {
+        let cfg = super::CheckTxCoreRpcConfig {
+            host: "127.0.0.1".to_string(),
+            port: 1,
+            username: String::new(),
+            password: String::new(),
+        };
+        assert_eq!(cfg.url(), "127.0.0.1:1");
+    }
+
+    /// `CoreConfig::default()` should be empty strings and zero port (covers
+    /// the auto-derived `Default` with both flattened members).
+    #[test]
+    fn core_config_default_is_empty() {
+        let cfg = CoreConfig::default();
+        assert_eq!(cfg.consensus_rpc.host, "");
+        assert_eq!(cfg.consensus_rpc.port, 0);
+        assert_eq!(cfg.check_tx_rpc.host, "");
+        assert_eq!(cfg.check_tx_rpc.port, 0);
+    }
+
+    // --- `default_for_network` dispatch, including the catch-all ---
+
+    /// Exercises the `Network::Mainnet`, `Network::Testnet`, `Network::Devnet`,
+    /// `Network::Regtest` arms of `default_for_network`.
+    #[test]
+    fn default_for_network_dispatches_all_known_networks() {
+        let mainnet = PlatformConfig::default_for_network(Network::Mainnet);
+        assert_eq!(mainnet.network, Network::Mainnet);
+        assert_eq!(mainnet.validator_set.quorum_type, QuorumType::Llmq100_67);
+
+        let testnet = PlatformConfig::default_for_network(Network::Testnet);
+        assert_eq!(testnet.network, Network::Testnet);
+        assert_eq!(testnet.validator_set.quorum_type, QuorumType::Llmq25_67);
+
+        let devnet = PlatformConfig::default_for_network(Network::Devnet);
+        // default_devnet currently sets network to Regtest (see impl).
+        assert_eq!(devnet.network, Network::Regtest);
+
+        let regtest = PlatformConfig::default_for_network(Network::Regtest);
+        assert_eq!(regtest.network, Network::Regtest);
+    }
+
+    // --- `ValidatorSetConfig::default_100_67` and QuorumLikeConfig getters ---
+
+    /// Exercises `default_100_67` + every getter in `QuorumLikeConfig` for
+    /// `ValidatorSetConfig` - these getters are pure accessors that would
+    /// otherwise be uncovered outside the actual consensus path.
+    #[test]
+    fn validator_set_default_100_67_accessors() {
+        let cfg = ValidatorSetConfig::default_100_67();
+        assert_eq!(cfg.quorum_type(), QuorumType::Llmq100_67);
+        assert_eq!(cfg.quorum_size(), 100);
+        assert_eq!(cfg.quorum_window(), 24);
+        assert_eq!(cfg.quorum_active_signers(), 24);
+        assert!(!cfg.quorum_rotation());
+    }
+
+    /// Same but for `ChainLockConfig::default_100_67`.
+    #[test]
+    fn chain_lock_default_100_67_accessors() {
+        let cfg = ChainLockConfig::default_100_67();
+        assert_eq!(cfg.quorum_type(), QuorumType::Llmq100_67);
+        assert_eq!(cfg.quorum_size(), 100);
+        assert_eq!(cfg.quorum_window(), 24);
+        assert_eq!(cfg.quorum_active_signers(), 24);
+        assert!(!cfg.quorum_rotation());
+    }
+
+    /// `ChainLockConfig::default()` is Mainnet LLMQ400_60 - cover all getters.
+    #[test]
+    fn chain_lock_default_is_llmq_400_60() {
+        let cfg = ChainLockConfig::default();
+        assert_eq!(cfg.quorum_type(), QuorumType::Llmq400_60);
+        assert_eq!(cfg.quorum_size(), 400);
+        assert_eq!(cfg.quorum_window(), 24 * 12);
+        assert_eq!(cfg.quorum_active_signers(), 4);
+        assert!(!cfg.quorum_rotation());
+    }
+
+    /// `InstantLockConfig::default()` is DIP24 rotated LLMQ60_75.
+    #[test]
+    fn instant_lock_default_is_llmq_60_75_rotated() {
+        let cfg = InstantLockConfig::default();
+        assert_eq!(cfg.quorum_type(), QuorumType::Llmq60_75);
+        assert_eq!(cfg.quorum_size(), 60);
+        assert_eq!(cfg.quorum_window(), 24 * 12);
+        assert_eq!(cfg.quorum_active_signers(), 32);
+        assert!(cfg.quorum_rotation());
+    }
+
+    /// `InstantLockConfig::default_100_67` is the classic LLMQ variant.
+    #[test]
+    fn instant_lock_default_100_67_accessors() {
+        let cfg = InstantLockConfig::default_100_67();
+        assert_eq!(cfg.quorum_type(), QuorumType::Llmq100_67);
+        assert_eq!(cfg.quorum_size(), 100);
+        assert_eq!(cfg.quorum_window(), 24);
+        assert_eq!(cfg.quorum_active_signers(), 24);
+        assert!(!cfg.quorum_rotation());
+    }
+
+    /// Exercises `PlatformConfig::default()` which delegates to `default_mainnet`.
+    #[test]
+    fn platform_config_default_is_mainnet() {
+        let cfg = PlatformConfig::default();
+        assert_eq!(cfg.network, Network::Mainnet);
+        assert_eq!(cfg.validator_set.quorum_type, QuorumType::Llmq100_67);
+        assert_eq!(cfg.chain_lock.quorum_type, QuorumType::Llmq400_60);
+        assert_eq!(cfg.instant_lock.quorum_type, QuorumType::Llmq60_75);
+        assert_eq!(cfg.block_spacing_ms, 5000);
+    }
+
+    // --- `ExecutionConfig` default values ---
+
+    /// Exercises all four default-provider functions on `ExecutionConfig`.
+    #[test]
+    fn execution_config_defaults() {
+        let cfg = super::ExecutionConfig::default();
+        assert!(cfg.verify_sum_trees);
+        assert!(cfg.verify_token_sum_trees);
+        assert!(cfg.use_document_triggers);
+        assert_eq!(cfg.epoch_time_length_s, 788400);
+    }
+
+    // --- `serialize_quorum_type` round-trip via Serialize ---
+
+    /// Covers the `serialize_quorum_type` codepath (symmetric pair of the
+    /// deserialize tests above).
+    #[test]
+    fn validator_set_config_serializes_quorum_type_as_string() {
+        let cfg = ValidatorSetConfig::default_100_67();
+        let json = serde_json::to_string(&cfg).expect("valid serialize");
+        // The serialized representation must use the textual form.
+        assert!(
+            json.contains("llmq_100_67") || json.contains("Llmq100_67"),
+            "expected textual quorum type in JSON, got: {}",
+            json
+        );
+    }
 }