diff --git a/python/python-psi-impl/src/com/jetbrains/python/inspections/PyStringFormatInspection.java b/python/python-psi-impl/src/com/jetbrains/python/inspections/PyStringFormatInspection.java
index 4dcb4223b1fb..631257e7371b 100644
--- a/python/python-psi-impl/src/com/jetbrains/python/inspections/PyStringFormatInspection.java
+++ b/python/python-psi-impl/src/com/jetbrains/python/inspections/PyStringFormatInspection.java
@@ -142,7 +142,9 @@ public final class PyStringFormatInspection extends PyInspection {
           }
           else {
             final PyTupleType tupleType = (PyTupleType)myTypeEvalContext.getType(rightExpression);
-            assert tupleType != null;
+            if (tupleType == null) {
+              return -1;
+            }
             matchEntireTupleTypes(problemTarget, tupleType);
             return tupleType.getElementCount();
           }
diff --git a/python/testData/inspections/PyStringFormatInspection/TupleFormat.py b/python/testData/inspections/PyStringFormatInspection/TupleFormat.py
new file mode 100644
index 000000000000..908c7e3f71a1
--- /dev/null
+++ b/python/testData/inspections/PyStringFormatInspection/TupleFormat.py
@@ -0,0 +1,2 @@
+a = ("b", "c")
+d = "%s" % a
\ No newline at end of file
diff --git a/python/testSrc/com/jetbrains/python/fixtures/PyTestCase.java b/python/testSrc/com/jetbrains/python/fixtures/PyTestCase.java
index c4bfbfc80dba..44972d704d6a 100644
--- a/python/testSrc/com/jetbrains/python/fixtures/PyTestCase.java
+++ b/python/testSrc/com/jetbrains/python/fixtures/PyTestCase.java
@@ -119,6 +119,10 @@ public abstract class PyTestCase extends UsefulTestCase {
 
   protected void assertSdkRootsNotParsed(@NotNull PsiFile currentFile) {
     final Sdk testSdk = PythonSdkUtil.findPythonSdk(currentFile);
+    if (testSdk == null) {
+      LOG.warn("testSdk is null. assertSdkRootsNotParsed is skipped");
+      return;
+    }
     for (VirtualFile root : testSdk.getRootProvider().getFiles(OrderRootType.CLASSES)) {
       assertRootNotParsed(currentFile, root, null);
     }
diff --git a/python/testSrc/com/jetbrains/python/inspections/PyStringFormatNoSDKInspectionTest.java b/python/testSrc/com/jetbrains/python/inspections/PyStringFormatNoSDKInspectionTest.java
new file mode 100644
index 000000000000..6a6da3d6c745
--- /dev/null
+++ b/python/testSrc/com/jetbrains/python/inspections/PyStringFormatNoSDKInspectionTest.java
@@ -0,0 +1,31 @@
+// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.jetbrains.python.inspections;
+
+import com.intellij.testFramework.LightProjectDescriptor;
+import com.jetbrains.python.fixtures.PyInspectionTestCase;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public class PyStringFormatNoSDKInspectionTest extends PyInspectionTestCase {
+
+  @Override
+  protected @Nullable LightProjectDescriptor getProjectDescriptor() {
+    return LightProjectDescriptor.EMPTY_PROJECT_DESCRIPTOR;
+  }
+
+  // PY-80147
+  public void testTupleFormat() {
+    doTest();
+  }
+
+  @NotNull
+  @Override
+  protected Class<? extends PyInspection> getInspectionClass() {
+    return PyStringFormatInspection.class;
+  }
+
+  @Override
+  protected boolean isLowerCaseTestFile() {
+    return false;
+  }
+}