PY-19884 Add a test on type checking of set collection

python/testData/inspections/PyTypeCheckerInspection/SetMethods.py

@@ -0,0 +1,9 @@
+xs = set([1, 2, 3])
+
+'foo' + <warning descr="Expected type 'Union[str, unicode]', got 'int' instead">xs.pop()</warning>
+xs.discard(<weak_warning descr="Expected type 'int' (matched generic type 'TypeVar('T')'), got 'str' instead">'foo'</weak_warning>)
+xs.remove(<weak_warning descr="Expected type 'int' (matched generic type 'TypeVar('T')'), got 'str' instead">'bar'</weak_warning>)
+xs.add(<weak_warning descr="Expected type 'int' (matched generic type 'TypeVar('T')'), got 'object' instead">object()</weak_warning>)
+
+ys = ['green', 'eggs']
+ys.extend(<weak_warning descr="Expected type 'Iterable[str]' (matched generic type 'Iterable[TypeVar('T')]'), got 'Set[int]' instead">xs</weak_warning>)

python/testSrc/com/jetbrains/python/inspections/PyTypeCheckerInspectionTest.java

@@ -300,4 +300,9 @@ public class PyTypeCheckerInspectionTest extends PyTestCase {
   public void testAbsSetAndMutableSet() {
     doTest();
   }
+
+  // PY-19884
+  public void testSetMethods() {
+    doTest();
+  }
 }