diff --git a/Lib/test/test_curses.py b/Lib/test/test_curses.py
--- a/Lib/test/test_curses.py
+++ b/Lib/test/test_curses.py
@@ -32,6 +32,22 @@
 if sys.platform == "cygwin":
     raise unittest.SkipTest("cygwin's curses mostly just hangs")
 
+def check_exception(exception_type, func, *args, msg=None):
+    """Confirm that the given function raises the given exception."""
+    try:
+        func(*args)
+    except exception_type as err:
+        if msg is not None and str(err) != msg:
+            raise RuntimeError("%s text %s does not match %s" %
+                               (exception_type.__name__, repr(str(err)),
+                                repr(msg)))
+    else:
+        runtime_msg = ("Expected function %s to raise %s" %
+                       (repr(func.__name__), exception_type.__name__))
+        if msg is not None:
+            runtime_msg += " with message: %s" % repr(msg)
+        raise RuntimeError(runtime_msg)
+
 def window_funcs(stdscr):
     "Test the methods of windows"
     win = curses.newwin(10,10)
@@ -48,7 +64,7 @@
                  stdscr.deleteln, stdscr.erase, stdscr.getbegyx,
                  stdscr.getbkgd, stdscr.getkey, stdscr.getmaxyx,
                  stdscr.getparyx, stdscr.getyx, stdscr.inch,
-                 stdscr.insertln, stdscr.instr, stdscr.is_wintouched,
+                 stdscr.insertln, stdscr.is_wintouched,
                  win.noutrefresh, stdscr.redrawwin, stdscr.refresh,
                  stdscr.standout, stdscr.standend, stdscr.syncdown,
                  stdscr.syncup, stdscr.touchwin, stdscr.untouchwin]:
@@ -71,13 +87,7 @@
                69, 70, 71, 72)
     win.border('|', '!', '-', '_',
                '+', '\\', '#', '/')
-    try:
-        win.border(65, 66, 67, 68,
-                   69, [], 71, 72)
-    except TypeError:
-        pass
-    else:
-        raise RuntimeError("Expected win.border() to raise TypeError")
+    check_exception(TypeError, win.border, 65, 66, 67, 68, 69, [], 71, 72)
 
     stdscr.clearok(1)
 
@@ -95,7 +105,22 @@
     stdscr.idcok(1)
     stdscr.idlok(1)
     stdscr.immedok(1)
+    # Test all valid numbers of arguments for window.insch() (and boundaries).
+    check_exception(TypeError, stdscr.insch,
+                    msg="insch requires 1 to 4 arguments")
     stdscr.insch('c')
+    stdscr.insch('c', curses.A_NORMAL)
+    stdscr.insch(0, 0, 'c')
+    stdscr.insch(0, 0, 'c', curses.A_NORMAL)
+    check_exception(TypeError, stdscr.insch, 0, 0, 'c', curses.A_NORMAL, 0,
+                    msg="insch requires 1 to 4 arguments")
+    # Test all valid numbers of arguments for window.instr() (and boundaries).
+    stdscr.instr()
+    stdscr.instr(0)
+    stdscr.instr(0, 0)
+    stdscr.instr(0, 0, 0)
+    check_exception(TypeError, stdscr.instr, 0, 0, 0, 0,
+                    msg="instr requires 0 to 3 arguments")
     stdscr.insdelln(1)
     stdscr.insnstr('abc', 3)
     stdscr.insnstr('abc', 3, curses.A_BOLD)
diff --git a/Modules/_cursesmodule.c b/Modules/_cursesmodule.c
--- a/Modules/_cursesmodule.c
+++ b/Modules/_cursesmodule.c
@@ -1319,7 +1319,7 @@
         use_xy = TRUE;
         break;
     default:
-        PyErr_SetString(PyExc_TypeError, "insch requires 1 or 4 arguments");
+        PyErr_SetString(PyExc_TypeError, "insch requires 1 to 4 arguments");
         return NULL;
     }
 
@@ -1382,7 +1382,7 @@
         rtn2 = mvwinnstr(self->win, y, x, rtn, MIN(n,1023));
         break;
     default:
-        PyErr_SetString(PyExc_TypeError, "instr requires 0 or 3 arguments");
+        PyErr_SetString(PyExc_TypeError, "instr requires 0 to 3 arguments");
         return NULL;
     }
     if (rtn2 == ERR)