patch 8.2.1151: insufficient test coverage for Python

Problem:    Insufficient test coverage for Python.
Solution:   Add more test cases. (Yegappan Lakshmanan, closes #6415)

src/testdir/test_python2.vim

@@ -623,6 +623,9 @@ func Test_python_slice_assignment()
   py l = vim.bindeval('l')
   py l[2:2:1] = ()
   call assert_equal([0, 1, 2, 3, 4, 5, 6, 7], l)
+
+  call AssertException(["py x = l[10:11:0]"],
+        \ "Vim(python):ValueError: slice step cannot be zero")
 endfunc
 
 " Locked variables
@@ -809,6 +812,10 @@ func Test_python_vim_bindeval()
   call assert_equal(0, pyeval("vim.bindeval('v:false')"))
   call assert_equal(v:none, pyeval("vim.bindeval('v:null')"))
   call assert_equal(v:none, pyeval("vim.bindeval('v:none')"))
+
+  " channel/job
+  call assert_equal(v:none, pyeval("vim.bindeval('test_null_channel()')"))
+  call assert_equal(v:none, pyeval("vim.bindeval('test_null_job()')"))
 endfunc
 
 " threading
@@ -1402,6 +1409,20 @@ func Test_python_buffer()
   call assert_equal([], pyeval('b[2:0]'))
   call assert_equal([], pyeval('b[10:12]'))
   call assert_equal([], pyeval('b[-10:-8]'))
+  call AssertException(["py x = b[0:3:0]"],
+        \ "Vim(python):TypeError: sequence index must be integer, not 'slice'")
+  call AssertException(["py b[0:3:0] = 'abc'"],
+        \ "Vim(python):TypeError: sequence index must be integer, not 'slice'")
+  call AssertException(["py x = b[{}]"],
+        \ "Vim(python):TypeError: sequence index must be integer, not 'dict'")
+  call AssertException(["py b[{}] = 'abc'"],
+        \ "Vim(python):TypeError: sequence index must be integer, not 'dict'")
+
+  " Test for getting lines using a range
+  call AssertException(["py x = b.range(0,3)[0:2:0]"],
+        \ "Vim(python):TypeError: sequence index must be integer, not 'slice'")
+  call AssertException(["py b.range(0,3)[0:2:0] = 'abc'"],
+        \ "Vim(python):TypeError: sequence index must be integer, not 'slice'")
 
   " Tests BufferAppend and BufferItem
   py cb.append(b[0])
@@ -1512,6 +1533,9 @@ func Test_python_buffer()
   py vim.current.buffer[:] = []
   call assert_equal([''], getline(1, '$'))
 
+  " Test for buffer marks
+  call assert_equal(v:none, pyeval("vim.current.buffer.mark('r')"))
+
   " Test for modifying a 'nomodifiable' buffer
   setlocal nomodifiable
   call AssertException(["py vim.current.buffer[0] = 'abc'"],
@@ -2408,6 +2432,7 @@ func Test_python_chdir()
   call assert_equal(['testdir', 'Xfile', 'src', 'testdir/Xfile', 'testdir',
         \ 'Xfile'], getline(2, '$'))
   close!
+  call AssertException(["py vim.chdir(None)"], "Vim(python):TypeError:")
 endfunc
 
 " Test errors

src/testdir/test_python3.vim

@@ -798,6 +798,9 @@ func Test_python3_slice_assignment()
   py3 l = vim.bindeval('l')
   py3 l[2:2:1] = ()
   call assert_equal([0, 1, 2, 3, 4, 5, 6, 7], l)
+
+  call AssertException(["py3 x = l[10:11:0]"],
+        \ "Vim(py3):ValueError: slice step cannot be zero")
 endfunc
 
 " Locked variables
@@ -987,6 +990,10 @@ func Test_python3_vim_bindeval()
   call assert_equal(0, py3eval("vim.bindeval('v:false')"))
   call assert_equal(v:none, py3eval("vim.bindeval('v:null')"))
   call assert_equal(v:none, py3eval("vim.bindeval('v:none')"))
+
+  " channel/job
+  call assert_equal(v:none, py3eval("vim.bindeval('test_null_channel()')"))
+  call assert_equal(v:none, py3eval("vim.bindeval('test_null_job()')"))
 endfunc
 
 " threading
@@ -1580,6 +1587,20 @@ func Test_python3_buffer()
   call assert_equal([], py3eval('b[2:0]'))
   call assert_equal([], py3eval('b[10:12]'))
   call assert_equal([], py3eval('b[-10:-8]'))
+  call AssertException(["py3 x = b[0:3:0]"],
+        \ 'Vim(py3):ValueError: slice step cannot be zero')
+  call AssertException(["py3 b[0:3:0] = 'abc'"],
+        \ 'Vim(py3):ValueError: slice step cannot be zero')
+  call AssertException(["py3 x = b[{}]"],
+        \ 'Vim(py3):TypeError: index must be int or slice, not dict')
+  call AssertException(["py3 b[{}] = 'abc'"],
+        \ 'Vim(py3):TypeError: index must be int or slice, not dict')
+
+  " Test for getting lines using a range
+  call AssertException(["py3 x = b.range(0,3)[0:2:0]"],
+        \ "Vim(py3):ValueError: slice step cannot be zero")
+  call AssertException(["py3 b.range(0,3)[0:2:0] = 'abc'"],
+        \ "Vim(py3):ValueError: slice step cannot be zero")
 
   " Tests BufferAppend and BufferItem
   py3 cb.append(b[0])
@@ -1690,6 +1711,9 @@ func Test_python3_buffer()
   py3 vim.current.buffer[:] = []
   call assert_equal([''], getline(1, '$'))
 
+  " Test for buffer marks
+  call assert_equal(v:none, py3eval("vim.current.buffer.mark('r')"))
+
   " Test for modifying a 'nomodifiable' buffer
   setlocal nomodifiable
   call AssertException(["py3 vim.current.buffer[0] = 'abc'"],
@@ -2578,6 +2602,7 @@ func Test_python3_chdir()
   call assert_equal(["b'testdir'", 'Xfile', "b'src'", 'testdir/Xfile',
         \"b'testdir'", 'Xfile'], getline(2, '$'))
   close!
+  call AssertException(["py3 vim.chdir(None)"], "Vim(py3):TypeError:")
 endfunc
 
 " Test errors

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1151,
 /**/
     1150,
 /**/