ropsten TTD config (#3871)

* ropsten TTD config

Signed-off-by: garyschulte <garyschulte@gmail.com>

CHANGELOG.md

@@ -6,6 +6,7 @@
 - GraphQL - allow null log topics in queries which match any topic [#3662](https://github.com/hyperledger/besu/pull/3662)
 - multi-arch docker builds for amd64 and arm64 [#2954](https://github.com/hyperledger/besu/pull/2954)
 - Filter Netty native lib errors likewise the pure Java implementation [#3807](https://github.com/hyperledger/besu/pull/3807)
+- Add ropsten terminal total difficulty config [#3871](https://github.com/hyperledger/besu/pull/3871)
 
 ### Bug Fixes
 - Stop the BlockPropagationManager when it receives the TTD reached event [#3809](https://github.com/hyperledger/besu/pull/3809)

config/src/main/java/org/hyperledger/besu/config/GenesisConfigFile.java

@@ -45,12 +45,7 @@ public class GenesisConfigFile {
   }
 
   public static GenesisConfigFile mainnet() {
-    try {
-      return fromConfig(
-          Resources.toString(GenesisConfigFile.class.getResource("/mainnet.json"), UTF_8));
-    } catch (final IOException e) {
-      throw new IllegalStateException(e);
-    }
+    return genesisFileFromResources("/mainnet.json");
   }
 
   public static ObjectNode mainnetJsonNode() {
@@ -64,18 +59,17 @@ public class GenesisConfigFile {
   }
 
   public static GenesisConfigFile development() {
-    try {
-      return fromConfig(
-          Resources.toString(GenesisConfigFile.class.getResource("/dev.json"), UTF_8));
-    } catch (final IOException e) {
-      throw new IllegalStateException(e);
-    }
+    return genesisFileFromResources("/dev.json");
   }
 
   public static GenesisConfigFile ecip1049dev() {
+    return genesisFileFromResources("/ecip1049_dev.json");
+  }
+
+  public static GenesisConfigFile genesisFileFromResources(final String resourceName) {
     try {
       return fromConfig(
-          Resources.toString(GenesisConfigFile.class.getResource("/ecip1049_dev.json"), UTF_8));
+          Resources.toString(GenesisConfigFile.class.getResource(resourceName), UTF_8));
     } catch (final IOException e) {
       throw new IllegalStateException(e);
     }

config/src/main/resources/ropsten.json

@@ -10,6 +10,7 @@
     "muirGlacierBlock": 7117117,
     "berlinBlock": 9812189,
     "londonBlock": 10499401,
+    "terminalTotalDifficulty": 43531756765713534,
     "ethash": {
     },
     "discovery": {

config/src/test/java/org/hyperledger/besu/config/GenesisConfigFileTest.java

@@ -198,6 +198,27 @@ public class GenesisConfigFileTest {
     assertThat(EMPTY_CONFIG.getConfigOptions().getTerminalTotalDifficulty()).isNotPresent();
   }
 
+  @Test
+  public void assertRopstenTerminalTotalDifficulty() {
+    GenesisConfigOptions ropstenOptions =
+        GenesisConfigFile.genesisFileFromResources("/ropsten.json").getConfigOptions();
+
+    assertThat(ropstenOptions.getTerminalTotalDifficulty()).isPresent();
+    assertThat(ropstenOptions.getTerminalTotalDifficulty().get())
+        .isEqualTo(UInt256.valueOf(43531756765713534L));
+  }
+
+  @Test
+  public void assertTerminalTotalDifficultyOverride() {
+    GenesisConfigOptions ropstenOverrideOptions =
+        GenesisConfigFile.genesisFileFromResources("/ropsten.json")
+            .getConfigOptions(Map.of("terminalTotalDifficulty", String.valueOf(Long.MAX_VALUE)));
+
+    assertThat(ropstenOverrideOptions.getTerminalTotalDifficulty()).isPresent();
+    assertThat(ropstenOverrideOptions.getTerminalTotalDifficulty().get())
+        .isEqualTo(UInt256.valueOf(Long.MAX_VALUE));
+  }
+
   @Test
   public void shouldFindParisForkAndAlias() {
     GenesisConfigFile parisGenesis =