adds todos

zebra-chain/src/parameters/network_upgrade.rs

@@ -271,8 +271,8 @@ impl Network {
         };
         match self {
             Mainnet => mainnet_heights,
-            Testnet(_params) if self.is_default_testnet() => testnet_heights,
-            Testnet(_) => unimplemented!("custom testnet activation heights"),
+            // TODO: Add `activation_heights` field and use the above Testnet constants as the default value
+            Testnet(_params) => testnet_heights,
         }
         .iter()
         .cloned()
@@ -393,18 +393,17 @@ impl NetworkUpgrade {
         height: block::Height,
     ) -> Option<Duration> {
         match (network, height) {
+            // TODO: Add a field on `NetworkParameters` for minimum difficulty spacing and min difficulty start height
             (Network::Testnet(_params), height)
-                if network.is_default_testnet()
-                    && height < TESTNET_MINIMUM_DIFFICULTY_START_HEIGHT =>
+                if height < TESTNET_MINIMUM_DIFFICULTY_START_HEIGHT =>
             {
                 None
             }
             (Network::Mainnet, _) => None,
-            (Network::Testnet(_params), _) if network.is_default_testnet() => {
+            (Network::Testnet(_params), _) => {
                 let network_upgrade = NetworkUpgrade::current(network, height);
                 Some(network_upgrade.target_spacing() * TESTNET_MINIMUM_DIFFICULTY_GAP_MULTIPLIER)
             }
-            _ => unimplemented!("custom testnet minimum difficulty spacing"),
         }
     }
 

zebra-chain/src/primitives/address.rs

@@ -65,6 +65,7 @@ impl TryFrom<Network> for zcash_address::Network {
             Network::Testnet(_params) if network.is_default_testnet() => {
                 Ok(zcash_address::Network::Test)
             }
+            // TODO: Check for Regtest parameters and return [`zcash_address::Network::Regtest`]
             Network::Testnet(_params) => Err(UnsupportedNetwork),
         }
     }

zebra-chain/src/work/difficulty.rs

@@ -699,11 +699,8 @@ impl ParameterDifficulty for Network {
             /* 2^243 - 1 */
             Network::Mainnet => (U256::one() << 243) - 1,
             /* 2^251 - 1 */
-            Network::Testnet(_) if self.is_default_testnet() => (U256::one() << 251) - 1,
-            // Custom value
-            Network::Testnet(_params) => {
-                unimplemented!("custom testnet target difficulty limit")
-            }
+            // TODO: Add a `target_difficulty_limit` field to `NetworkParameters` and return the field
+            Network::Testnet(_) => (U256::one() << 251) - 1,
         };
 
         // `zcashd` converts the PoWLimit into a compact representation before