Use appropriate engine in flow

Author: EgorkaKulikov

utbot-framework/src/main/kotlin/org/utbot/engine/UsvmSymbolicEngine.kt

@@ -0,0 +1,10 @@
+package org.utbot.engine
+
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.emptyFlow
+import org.utbot.framework.plugin.api.UtResult
+
+class UsvmSymbolicEngine {
+
+    fun generateWithUsvm(): Flow<UtResult> = emptyFlow()
+}

utbot-framework/src/main/kotlin/org/utbot/framework/plugin/api/TestFlow.kt

@@ -4,10 +4,10 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.emptyFlow
 import kotlinx.coroutines.flow.flattenConcat
 import kotlinx.coroutines.flow.flowOf
+import org.utbot.engine.UsvmSymbolicEngine
 import org.utbot.engine.UtBotSymbolicEngine
 import org.utbot.framework.UtSettings
 import org.utbot.framework.codegen.domain.SymbolicEngineSource
-import org.utbot.framework.process.generated.GenerateParams
 
 /**
  * Constructs [TestFlow] for customization and creates flow producer.
@@ -73,7 +73,12 @@ class TestFlow internal constructor(block: TestFlow.() -> Unit) {
                     ).flattenConcat()
                 }
             }
-            isSymbolicEngineEnabled -> engine.traverse()
+            isSymbolicEngineEnabled -> {
+                when (symbolicEngineType) {
+                    SymbolicEngineSource.UnitTestBot -> engine.traverse()
+                    SymbolicEngineSource.Usvm -> UsvmSymbolicEngine().generateWithUsvm()
+                }
+            }
             else -> emptyFlow()
         }
     }