diff --git a/ij/src/main/kotlin/org/jetbrains/academy/test/system/ij/analyzer/IjCodeAnalyzerUtil.kt b/ij/src/main/kotlin/org/jetbrains/academy/test/system/ij/analyzer/IjCodeAnalyzerUtil.kt
index a4e8f52..a79ab0e 100644
--- a/ij/src/main/kotlin/org/jetbrains/academy/test/system/ij/analyzer/IjCodeAnalyzerUtil.kt
+++ b/ij/src/main/kotlin/org/jetbrains/academy/test/system/ij/analyzer/IjCodeAnalyzerUtil.kt
@@ -126,7 +126,7 @@ private fun getParentText(element: PsiElement, isParentTypeFunction: Boolean): S
  *                            If false, the parent element is expected to be a class or any other non-function type.
  * @return True if the PsiFile contains an expression with the given text and the specified parent, false otherwise.
  */
-fun PsiFile.hasExpressionWithParent(expression: String, parent: String, isParentTypeFunction: Boolean): Boolean =
+fun PsiFile.hasExpressionWithParent(expression: String, parent: String?, isParentTypeFunction: Boolean): Boolean =
     ApplicationManager.getApplication().runReadAction<Boolean> {
         val expressions: MutableCollection<PsiElement> =
             extractElementsOfTypes(KtDotQualifiedExpression::class.java, KtCallExpression::class.java)
diff --git a/ij/src/main/kotlin/org/jetbrains/academy/test/system/test/BaseIjTestClass.kt b/ij/src/main/kotlin/org/jetbrains/academy/test/system/test/BaseIjTestClass.kt
index edaaeef..7c97a67 100644
--- a/ij/src/main/kotlin/org/jetbrains/academy/test/system/test/BaseIjTestClass.kt
+++ b/ij/src/main/kotlin/org/jetbrains/academy/test/system/test/BaseIjTestClass.kt
@@ -23,6 +23,6 @@ open class BaseIjTestClass : BasePlatformTestCase() {
 
     fun hasMethod(methodName: String): Boolean = myFixture.file.hasMethod(methodName)
 
-    fun hasExpressionWithParent(expression: String, parent: String, isParentTypeFunction: Boolean = false): Boolean =
+    fun hasExpressionWithParent(expression: String, parent: String?, isParentTypeFunction: Boolean = false): Boolean =
         myFixture.file.hasExpressionWithParent(expression, parent, isParentTypeFunction)
 }
diff --git a/ij/src/test/kotlin/org/jetbrains/academy/test/system/ij/formatting/BaseIjTestClassTests.kt b/ij/src/test/kotlin/org/jetbrains/academy/test/system/ij/formatting/BaseIjTestClassTests.kt
index 6205d30..b1c924a 100644
--- a/ij/src/test/kotlin/org/jetbrains/academy/test/system/ij/formatting/BaseIjTestClassTests.kt
+++ b/ij/src/test/kotlin/org/jetbrains/academy/test/system/ij/formatting/BaseIjTestClassTests.kt
@@ -194,8 +194,8 @@ class BaseIjTestClassTests : BaseIjTestClass() {
             }
         """.trimIndent()
         myFixture.configureByText("Task.kt", example)
-        var expression = "productPrice.sum()"
-        var parent = "productPrice.sum() / productPrice.count()"
+        var expression: String = "productPrice.sum()"
+        var parent: String? = "productPrice.sum() / productPrice.count()"
         assert(hasExpressionWithParent(expression, parent)) {
             "There must exist an expression $expression with parent $parent"
         }
@@ -212,5 +212,10 @@ class BaseIjTestClassTests : BaseIjTestClass() {
         expression = "Int.MAX_VALUE"
         parent = "val CONSTANT = Int.MAX_VALUE"
         assertFalse(hasExpressionWithParent(expression, parent))
+        expression = "Int.MAX_VALUE"
+        parent = null
+        assert(hasExpressionWithParent(expression, parent, true)) {
+            "There must exist an expression $expression with parent $parent"
+        }
     }
 }