diff --git a/platform/smRunner/src/com/intellij/execution/testframework/sm/runner/OutputLineSplitter.java b/platform/smRunner/src/com/intellij/execution/testframework/sm/runner/OutputLineSplitter.java
index 8e5e141d37cc..a4a638b96ceb 100644
--- a/platform/smRunner/src/com/intellij/execution/testframework/sm/runner/OutputLineSplitter.java
+++ b/platform/smRunner/src/com/intellij/execution/testframework/sm/runner/OutputLineSplitter.java
@@ -101,7 +101,8 @@ public abstract class OutputLineSplitter {
       //    we can safely flush buffer.
 
       // TODO if editable:
-      if (myStdinSupportEnabled && !isMostLikelyServiceMessagePart(text)) {
+      if (myStdinSupportEnabled && !isInTeamcityMessage()) {
+        // We should not flush in the middle of TC message because of [PY-7659]
         flushStdOutBuffer();
       }
     }
@@ -150,8 +151,11 @@ public abstract class OutputLineSplitter {
     }
   }
 
-  protected boolean isMostLikelyServiceMessagePart(@NotNull final String text) {
-    return text.startsWith(TEAMCITY_SERVICE_MESSAGE_PREFIX);
+  /**
+   * @return if current stdout cache contains part of TC message.
+   */
+  protected boolean isInTeamcityMessage() {
+    return myStdOutChunks.stream().anyMatch(chunk -> chunk.getText().startsWith(TEAMCITY_SERVICE_MESSAGE_PREFIX));
   }
 
   protected abstract void onLineAvailable(@NotNull String text, @NotNull Key outputType, boolean tcLikeFakeOutput);
diff --git a/python/src/com/jetbrains/python/testing/PythonTRunnerConsoleProperties.java b/python/src/com/jetbrains/python/testing/PythonTRunnerConsoleProperties.java
index 31dded76fce7..46eb2fc28511 100644
--- a/python/src/com/jetbrains/python/testing/PythonTRunnerConsoleProperties.java
+++ b/python/src/com/jetbrains/python/testing/PythonTRunnerConsoleProperties.java
@@ -33,6 +33,9 @@ public class PythonTRunnerConsoleProperties extends SMTRunnerConsoleProperties {
 
   private final boolean myIsEditable;
 
+  /**
+   * @param editable if user should have ability to print something to test stdin
+   */
   public PythonTRunnerConsoleProperties(@NotNull ModuleRunConfiguration config, @NotNull Executor executor, boolean editable) {
     super(config, FRAMEWORK_NAME, executor);
     myIsEditable = editable;