[1.18] Integrate the gametest framework with Forge (#8225)

Signed-off-by: SizableShrimp <sizableshrimp@sizableshrimp.me>

build.gradle

@@ -55,6 +55,9 @@ minecraft {
             // Please read: https://stackoverflow.com/questions/2031163/when-to-use-the-different-log-levels
             property 'forge.logging.console.level', 'debug'
 
+            // Comma-separated list of namespaces to load gametests from. Empty = all namespaces.
+            property 'forge.enabledGameTestNamespaces', 'examplemod'
+
             mods {
                 examplemod {
                     source sourceSets.main
@@ -77,6 +80,37 @@ minecraft {
             // Please read: https://stackoverflow.com/questions/2031163/when-to-use-the-different-log-levels
             property 'forge.logging.console.level', 'debug'
 
+            // Comma-separated list of namespaces to load gametests from. Empty = all namespaces.
+            property 'forge.enabledGameTestNamespaces', 'examplemod'
+
+            mods {
+                examplemod {
+                    source sourceSets.main
+                }
+            }
+        }
+
+        // This run config launches GameTestServer and runs all registered gametests, then exits.
+        // By default, the server will crash when no gametests are provided.
+        // The gametest system is also enabled by default for other run configs under the /test command.
+        gameTestServer {
+            workingDirectory project.file('run')
+
+            // Recommended logging data for a userdev environment
+            // The markers can be added/remove as needed separated by commas.
+            // "SCAN": For mods scan.
+            // "REGISTRIES": For firing of registry events.
+            // "REGISTRYDUMP": For getting the contents of all registries.
+            property 'forge.logging.markers', 'REGISTRIES'
+
+            // Recommended logging level for the console
+            // You can set various levels here.
+            // Please read: https://stackoverflow.com/questions/2031163/when-to-use-the-different-log-levels
+            property 'forge.logging.console.level', 'debug'
+
+            // Comma-separated list of namespaces to load gametests from. Empty = all namespaces.
+            property 'forge.enabledGameTestNamespaces', 'examplemod'
+
             mods {
                 examplemod {
                     source sourceSets.main