I have a simple script which parses a file and loads it's contents to a database. I don't need a UI, but right now I'm prompting the user for the file to parse using raw_input which is most unfriendly, especially because the user can't copy/paste the path. I would like a quick and easy way to present a file selection dialog to the user, they can select the file, and then it's loaded to the database. (In my use case, if they happened to chose the wrong file, it would fail parsing, and wouldn't be a problem even if it was loaded to the database.)
import tkFileDialog
file_path_string = tkFileDialog.askopenfilename()
This code is close to what I want, but it leaves an annoying empty frame open (which isn't able to be closed, probably because I haven't registered a close event handler).
I don't have to use tkInter, but since it's in the Python standard library it's a good candidate for quickest and easiest solution.
Whats a quick and easy way to prompt for a file or filename in a script without any other UI?
Tkinter is the easiest way if you don't want to have any other dependencies.
To show only the dialog without any other GUI elements, you have to hide the root window using the withdraw method:
import tkinter as tk
from tkinter import filedialog
root = tk.Tk()
root.withdraw()
file_path = filedialog.askopenfilename()
Python 2 variant:
import Tkinter, tkFileDialog
root = Tkinter.Tk()
root.withdraw()
file_path = tkFileDialog.askopenfilename()
You can use easygui:
import easygui
path = easygui.fileopenbox()
To install easygui, you can use pip:
pip3 install easygui
It is a single pure Python module (easygui.py) that uses tkinter.
Try with wxPython:
import wx
def get_path(wildcard):
app = wx.App(None)
style = wx.FD_OPEN | wx.FD_FILE_MUST_EXIST
dialog = wx.FileDialog(None, 'Open', wildcard=wildcard, style=style)
if dialog.ShowModal() == wx.ID_OK:
path = dialog.GetPath()
else:
path = None
dialog.Destroy()
return path
print get_path('*.txt')
pywin32 provides access to the GetOpenFileName win32 function. From the example
import win32gui, win32con, os
filter='Python Scripts\0*.py;*.pyw;*.pys\0Text files\0*.txt\0'
customfilter='Other file types\0*.*\0'
fname, customfilter, flags=win32gui.GetOpenFileNameW(
InitialDir=os.environ['temp'],
Flags=win32con.OFN_ALLOWMULTISELECT|win32con.OFN_EXPLORER,
File='somefilename', DefExt='py',
Title='GetOpenFileNameW',
Filter=filter,
CustomFilter=customfilter,
FilterIndex=0)
print 'open file names:', repr(fname)
print 'filter used:', repr(customfilter)
print 'Flags:', flags
for k,v in win32con.__dict__.items():
if k.startswith('OFN_') and flags & v:
print '\t'+k
Using tkinter (python 2) or Tkinter (python 3) it's indeed possible to display file open dialog (See other answers here). Please notice however that user interface of that dialog is outdated and does not corresponds to newer file open dialogs available in Windows 10.
Moreover - if you're looking on way to embedd python support into your own application - you will find out soon that tkinter library is not open source code and even more - it is commercial library.
(For example search for "activetcl pricing" will lead you to this web page: https://reviews.financesonline.com/p/activetcl/)
So tkinter library will cost money for any application wanting to embedd python.
I by myself managed to find pythonnet library:
Overview here: http://pythonnet.github.io/
Source code here: https://github.com/pythonnet/pythonnet
(MIT License)
Using following command it's possible to install pythonnet:
pip3 install pythonnet
And here you can find out working example for using open file dialog:
https://stackoverflow.com/a/50446803/2338477
Let me copy an example also here:
import sys
import ctypes
co_initialize = ctypes.windll.ole32.CoInitialize
# Force STA mode
co_initialize(None)
import clr
clr.AddReference('System.Windows.Forms')
from System.Windows.Forms import OpenFileDialog
file_dialog = OpenFileDialog()
ret = file_dialog.ShowDialog()
if ret != 1:
print("Cancelled")
sys.exit()
print(file_dialog.FileName)
If you also miss more complex user interface - see Demo folder
in pythonnet git.
I'm not sure about portability to other OS's, haven't tried, but .net 5 is planned to be ported to multiple OS's (Search ".net 5 platforms", https://devblogs.microsoft.com/dotnet/introducing-net-5/ ) - so this technology is also future proof.
If you don't need the UI or expect the program to run in a CLI, you could parse the filepath as an argument. This would allow you to use the autocomplete feature of your CLI to quickly find the file you need.
This would probably only be handy if the script is non-interactive besides the filepath input.
Another os-agnostic option, use pywebview:
import webview
def webview_file_dialog():
file = None
def open_file_dialog(w):
nonlocal file
try:
file = w.create_file_dialog(webview.OPEN_DIALOG)[0]
except TypeError:
pass # user exited file dialog without picking
finally:
w.destroy()
window = webview.create_window("", hidden=True)
webview.start(open_file_dialog, window)
# file will either be a string or None
return file
print(webview_file_dialog())
Environment: python3.8.6 on Mac - though I've used pywebview on windows 10 before.
I just stumbled on this little trick for Windows only: run powershell.exe from subprocess.
import subprocess
sys_const = ssfDESKTOP # Starts at the top level
# sys_const = 0x2a # Correct value for "Program Files (0x86)" folder
powershell_browse = "(new-object -COM 'Shell.Application')."
powershell_browse += "BrowseForFolder(0,'window title here',0,sys_const).self.path"
ret = subprocess.run(["powershell.exe",powershell_browse], stdout=subprocess.PIPE)
print(ret.stdout.decode())
Note the optional use of system folder constants. (There's an obscure typo in shldisp.h that the "Program Files (0x86)" constant was assigned wrong. I added a comment with the correct value. Took me a bit to figure that one out.)
More info below:
System folder constants
Related
This question is focused on Windows + LibreOffice + Python 3.
I've installed LibreOffice (6.3.4.2), also
pip install unoconv and pip install unotools (pip install uno is another unrelated library), but still I get this error after import uno:
ModuleNotFoundError: No module named 'uno'
More generally, and as an example of use of UNO, how to open a .docx document with LibreOffice UNO and export it to PDF?
I've searched extensively on this since a few days, but I haven't found a reproducible sample code working on Windows:
headless use of soffice.exe, see my question+answer Headless LibreOffice very slow to export to PDF on Windows (6 times slow than on Linux) and the notes on the answer: it "works" with soffice.exe --headless ... but something closer to a COM interaction (Component Object Model) would be useful for many applications, thus this question here
Related forum post, and LibreOffice: Programming with Python Scripts, but the way uno should be installed on Windows, with Python, is not detailed; also Detailed tutorial regarding LibreOffice to Python macro writing, especially for Calc
I've also tried this (unsuccessfully): Getting python to import uno / pyuno:
import os
os.environ["URE_BOOTSTRAP"] = r"vnd.sun.star.pathname:C:\Program Files\LibreOffice\program\fundamental.ini"
os.environ["PATH"] += r";C:\Program Files\LibreOffice\program"
import uno
In order to interact with LibreOffice, start an instance listening on a socket. I don't use COM much, but I think this is the equivalent of the COM interaction you asked about. This can be done most easily on the command line or using a shell script, but it can also work with a system call using a time delay and subprocess.
chdir "%ProgramFiles%\LibreOffice\program\"
start soffice -accept=socket,host=localhost,port=2002;urp;
Next, run the installation of python that comes with LibreOffice, which has uno installed by default.
"C:\Program Files\LibreOffice\program\python.exe"
>> import uno
If instead you are using an installation of Python on Windows that was not shipped with LibreOffice, then getting it to work with UNO is much more difficult, and I would not recommend it unless you enjoy hacking.
Now, here is all the code. In a real project, it's probably best to organize into classes, but this is a simplified version.
import os
import uno
from com.sun.star.beans import PropertyValue
def createProp(name, value):
prop = PropertyValue()
prop.Name = name
prop.Value = value
return prop
localContext = uno.getComponentContext()
resolver = localContext.ServiceManager.createInstanceWithContext(
"com.sun.star.bridge.UnoUrlResolver", localContext)
ctx = resolver.resolve(
"uno:socket,host=localhost,port=2002;urp;"
"StarOffice.ComponentContext")
smgr = ctx.ServiceManager
desktop = smgr.createInstanceWithContext(
"com.sun.star.frame.Desktop", ctx)
dispatcher = smgr.createInstanceWithContext(
"com.sun.star.frame.DispatchHelper", ctx)
filepath = r"C:\Users\JimStandard\Desktop\Untitled 1.docx"
fileUrl = uno.systemPathToFileUrl(os.path.realpath(filepath))
uno_args = (
createProp("Minimized", True),
)
document = desktop.loadComponentFromURL(
fileUrl, "_default", 0, uno_args)
uno_args = (
createProp("FilterName", "writer_pdf_Export"),
createProp("Overwrite", False),
)
newpath = filepath[:-len("docx")] + "pdf"
fileUrl = uno.systemPathToFileUrl(os.path.realpath(newpath))
try:
document.storeToURL(fileUrl, uno_args) # Export
except ErrorCodeIOException:
raise
try:
document.close(True)
except CloseVetoException:
raise
Finally, since speed is a concern, using a listening instance of LibreOffice can be slow. To do this faster, move the code into a macro. APSO provides a menu to organize Python macros. Then call the macro like this:
soffice "vnd.sun.star.script:myscript.py$name_of_maindef?language=Python&location=user"
In macros, obtain the document objects from XSCRIPTCONTEXT rather than the resolver.
I have a simple script which parses a file and loads it's contents to a database. I don't need a UI, but right now I'm prompting the user for the file to parse using raw_input which is most unfriendly, especially because the user can't copy/paste the path. I would like a quick and easy way to present a file selection dialog to the user, they can select the file, and then it's loaded to the database. (In my use case, if they happened to chose the wrong file, it would fail parsing, and wouldn't be a problem even if it was loaded to the database.)
import tkFileDialog
file_path_string = tkFileDialog.askopenfilename()
This code is close to what I want, but it leaves an annoying empty frame open (which isn't able to be closed, probably because I haven't registered a close event handler).
I don't have to use tkInter, but since it's in the Python standard library it's a good candidate for quickest and easiest solution.
Whats a quick and easy way to prompt for a file or filename in a script without any other UI?
Tkinter is the easiest way if you don't want to have any other dependencies.
To show only the dialog without any other GUI elements, you have to hide the root window using the withdraw method:
import tkinter as tk
from tkinter import filedialog
root = tk.Tk()
root.withdraw()
file_path = filedialog.askopenfilename()
Python 2 variant:
import Tkinter, tkFileDialog
root = Tkinter.Tk()
root.withdraw()
file_path = tkFileDialog.askopenfilename()
You can use easygui:
import easygui
path = easygui.fileopenbox()
To install easygui, you can use pip:
pip3 install easygui
It is a single pure Python module (easygui.py) that uses tkinter.
Try with wxPython:
import wx
def get_path(wildcard):
app = wx.App(None)
style = wx.FD_OPEN | wx.FD_FILE_MUST_EXIST
dialog = wx.FileDialog(None, 'Open', wildcard=wildcard, style=style)
if dialog.ShowModal() == wx.ID_OK:
path = dialog.GetPath()
else:
path = None
dialog.Destroy()
return path
print get_path('*.txt')
pywin32 provides access to the GetOpenFileName win32 function. From the example
import win32gui, win32con, os
filter='Python Scripts\0*.py;*.pyw;*.pys\0Text files\0*.txt\0'
customfilter='Other file types\0*.*\0'
fname, customfilter, flags=win32gui.GetOpenFileNameW(
InitialDir=os.environ['temp'],
Flags=win32con.OFN_ALLOWMULTISELECT|win32con.OFN_EXPLORER,
File='somefilename', DefExt='py',
Title='GetOpenFileNameW',
Filter=filter,
CustomFilter=customfilter,
FilterIndex=0)
print 'open file names:', repr(fname)
print 'filter used:', repr(customfilter)
print 'Flags:', flags
for k,v in win32con.__dict__.items():
if k.startswith('OFN_') and flags & v:
print '\t'+k
Using tkinter (python 2) or Tkinter (python 3) it's indeed possible to display file open dialog (See other answers here). Please notice however that user interface of that dialog is outdated and does not corresponds to newer file open dialogs available in Windows 10.
Moreover - if you're looking on way to embedd python support into your own application - you will find out soon that tkinter library is not open source code and even more - it is commercial library.
(For example search for "activetcl pricing" will lead you to this web page: https://reviews.financesonline.com/p/activetcl/)
So tkinter library will cost money for any application wanting to embedd python.
I by myself managed to find pythonnet library:
Overview here: http://pythonnet.github.io/
Source code here: https://github.com/pythonnet/pythonnet
(MIT License)
Using following command it's possible to install pythonnet:
pip3 install pythonnet
And here you can find out working example for using open file dialog:
https://stackoverflow.com/a/50446803/2338477
Let me copy an example also here:
import sys
import ctypes
co_initialize = ctypes.windll.ole32.CoInitialize
# Force STA mode
co_initialize(None)
import clr
clr.AddReference('System.Windows.Forms')
from System.Windows.Forms import OpenFileDialog
file_dialog = OpenFileDialog()
ret = file_dialog.ShowDialog()
if ret != 1:
print("Cancelled")
sys.exit()
print(file_dialog.FileName)
If you also miss more complex user interface - see Demo folder
in pythonnet git.
I'm not sure about portability to other OS's, haven't tried, but .net 5 is planned to be ported to multiple OS's (Search ".net 5 platforms", https://devblogs.microsoft.com/dotnet/introducing-net-5/ ) - so this technology is also future proof.
If you don't need the UI or expect the program to run in a CLI, you could parse the filepath as an argument. This would allow you to use the autocomplete feature of your CLI to quickly find the file you need.
This would probably only be handy if the script is non-interactive besides the filepath input.
Another os-agnostic option, use pywebview:
import webview
def webview_file_dialog():
file = None
def open_file_dialog(w):
nonlocal file
try:
file = w.create_file_dialog(webview.OPEN_DIALOG)[0]
except TypeError:
pass # user exited file dialog without picking
finally:
w.destroy()
window = webview.create_window("", hidden=True)
webview.start(open_file_dialog, window)
# file will either be a string or None
return file
print(webview_file_dialog())
Environment: python3.8.6 on Mac - though I've used pywebview on windows 10 before.
I just stumbled on this little trick for Windows only: run powershell.exe from subprocess.
import subprocess
sys_const = ssfDESKTOP # Starts at the top level
# sys_const = 0x2a # Correct value for "Program Files (0x86)" folder
powershell_browse = "(new-object -COM 'Shell.Application')."
powershell_browse += "BrowseForFolder(0,'window title here',0,sys_const).self.path"
ret = subprocess.run(["powershell.exe",powershell_browse], stdout=subprocess.PIPE)
print(ret.stdout.decode())
Note the optional use of system folder constants. (There's an obscure typo in shldisp.h that the "Program Files (0x86)" constant was assigned wrong. I added a comment with the correct value. Took me a bit to figure that one out.)
More info below:
System folder constants
I have a simple script which parses a file and loads it's contents to a database. I don't need a UI, but right now I'm prompting the user for the file to parse using raw_input which is most unfriendly, especially because the user can't copy/paste the path. I would like a quick and easy way to present a file selection dialog to the user, they can select the file, and then it's loaded to the database. (In my use case, if they happened to chose the wrong file, it would fail parsing, and wouldn't be a problem even if it was loaded to the database.)
import tkFileDialog
file_path_string = tkFileDialog.askopenfilename()
This code is close to what I want, but it leaves an annoying empty frame open (which isn't able to be closed, probably because I haven't registered a close event handler).
I don't have to use tkInter, but since it's in the Python standard library it's a good candidate for quickest and easiest solution.
Whats a quick and easy way to prompt for a file or filename in a script without any other UI?
Tkinter is the easiest way if you don't want to have any other dependencies.
To show only the dialog without any other GUI elements, you have to hide the root window using the withdraw method:
import tkinter as tk
from tkinter import filedialog
root = tk.Tk()
root.withdraw()
file_path = filedialog.askopenfilename()
Python 2 variant:
import Tkinter, tkFileDialog
root = Tkinter.Tk()
root.withdraw()
file_path = tkFileDialog.askopenfilename()
You can use easygui:
import easygui
path = easygui.fileopenbox()
To install easygui, you can use pip:
pip3 install easygui
It is a single pure Python module (easygui.py) that uses tkinter.
Try with wxPython:
import wx
def get_path(wildcard):
app = wx.App(None)
style = wx.FD_OPEN | wx.FD_FILE_MUST_EXIST
dialog = wx.FileDialog(None, 'Open', wildcard=wildcard, style=style)
if dialog.ShowModal() == wx.ID_OK:
path = dialog.GetPath()
else:
path = None
dialog.Destroy()
return path
print get_path('*.txt')
pywin32 provides access to the GetOpenFileName win32 function. From the example
import win32gui, win32con, os
filter='Python Scripts\0*.py;*.pyw;*.pys\0Text files\0*.txt\0'
customfilter='Other file types\0*.*\0'
fname, customfilter, flags=win32gui.GetOpenFileNameW(
InitialDir=os.environ['temp'],
Flags=win32con.OFN_ALLOWMULTISELECT|win32con.OFN_EXPLORER,
File='somefilename', DefExt='py',
Title='GetOpenFileNameW',
Filter=filter,
CustomFilter=customfilter,
FilterIndex=0)
print 'open file names:', repr(fname)
print 'filter used:', repr(customfilter)
print 'Flags:', flags
for k,v in win32con.__dict__.items():
if k.startswith('OFN_') and flags & v:
print '\t'+k
Using tkinter (python 2) or Tkinter (python 3) it's indeed possible to display file open dialog (See other answers here). Please notice however that user interface of that dialog is outdated and does not corresponds to newer file open dialogs available in Windows 10.
Moreover - if you're looking on way to embedd python support into your own application - you will find out soon that tkinter library is not open source code and even more - it is commercial library.
(For example search for "activetcl pricing" will lead you to this web page: https://reviews.financesonline.com/p/activetcl/)
So tkinter library will cost money for any application wanting to embedd python.
I by myself managed to find pythonnet library:
Overview here: http://pythonnet.github.io/
Source code here: https://github.com/pythonnet/pythonnet
(MIT License)
Using following command it's possible to install pythonnet:
pip3 install pythonnet
And here you can find out working example for using open file dialog:
https://stackoverflow.com/a/50446803/2338477
Let me copy an example also here:
import sys
import ctypes
co_initialize = ctypes.windll.ole32.CoInitialize
# Force STA mode
co_initialize(None)
import clr
clr.AddReference('System.Windows.Forms')
from System.Windows.Forms import OpenFileDialog
file_dialog = OpenFileDialog()
ret = file_dialog.ShowDialog()
if ret != 1:
print("Cancelled")
sys.exit()
print(file_dialog.FileName)
If you also miss more complex user interface - see Demo folder
in pythonnet git.
I'm not sure about portability to other OS's, haven't tried, but .net 5 is planned to be ported to multiple OS's (Search ".net 5 platforms", https://devblogs.microsoft.com/dotnet/introducing-net-5/ ) - so this technology is also future proof.
If you don't need the UI or expect the program to run in a CLI, you could parse the filepath as an argument. This would allow you to use the autocomplete feature of your CLI to quickly find the file you need.
This would probably only be handy if the script is non-interactive besides the filepath input.
Another os-agnostic option, use pywebview:
import webview
def webview_file_dialog():
file = None
def open_file_dialog(w):
nonlocal file
try:
file = w.create_file_dialog(webview.OPEN_DIALOG)[0]
except TypeError:
pass # user exited file dialog without picking
finally:
w.destroy()
window = webview.create_window("", hidden=True)
webview.start(open_file_dialog, window)
# file will either be a string or None
return file
print(webview_file_dialog())
Environment: python3.8.6 on Mac - though I've used pywebview on windows 10 before.
I just stumbled on this little trick for Windows only: run powershell.exe from subprocess.
import subprocess
sys_const = ssfDESKTOP # Starts at the top level
# sys_const = 0x2a # Correct value for "Program Files (0x86)" folder
powershell_browse = "(new-object -COM 'Shell.Application')."
powershell_browse += "BrowseForFolder(0,'window title here',0,sys_const).self.path"
ret = subprocess.run(["powershell.exe",powershell_browse], stdout=subprocess.PIPE)
print(ret.stdout.decode())
Note the optional use of system folder constants. (There's an obscure typo in shldisp.h that the "Program Files (0x86)" constant was assigned wrong. I added a comment with the correct value. Took me a bit to figure that one out.)
More info below:
System folder constants
I am using pygtk to create a file chooser widget. I am using Ubuntu OS. I want to put a filter in selecting files. My chooser widget should only select executable files (diamond icons or in Ubuntu). I am trying to use below code:
dialog = gtk.FileChooserDialog(title=None,action=gtk.FILE_CHOOSER_ACTION_OPEN,
buttons=(gtk.STOCK_CANCEL,gtk.RESPONSE_CANCEL,gtk.STOCK_OK,gtk.RESPONSE_OK))
filter_file = gtk.FileFilter()
filter_file.add_pattern("*.bin")
filter_file.add_pattern("*.run")
filter_file.add_pattern("*.sh")
dialog.add_filter(filter_images)
dialog.show()
It is not working. It does not show the executable files in chooser window. Is there any way we can put filter on executable files because it seems like Ubuntu does not have any extension for executable files.
I'm not familiar with gtk, but a quick look at the docs for gtk.FileFilter leads me to believe that using FileFilter.add_custom instead of FileFilter.add_pattern will allow you to write a custom filter function that can get the permission bits for the file to determine if it is executable or not. For example:
import os
def executable_filter(filter_info, data):
path = filter_info[0]
# Note that this only checks if the current effective user may execute the file. If you need to know if owner/group/other can execute it, you'll probably want something from the os.stat module.
return os.access(path, os.X_OK)
filter_file.add_custom((gtk.FILE_FILTER_FILENAME, None, None, None), executable_filter, None)
I can't test this, because I don't have gtk set up, but I think this approach will work.
Question
Is there any way to automate a tkFileDialog selection to run it through unittest? The following is the only use of tkinter in my application:
root = Tkinter.Tk()
types = [('Comma Separated Values', '.csv'), ('All Files', '*')]
filename = tkFileDialog.askopenfilename(parent=root,
filetypes=types)
root.destroy()
Edit: I didn't mention that this part of the code was trapped in a method call from a class outside my control.
Background
I've built a local app that creates an http server on localhost and runs its GUI with HTML/CSS/JS in a web browser. Because of browser restrictions, I can't use the built-in file dialog and so have to send this request through Python. I want this to run on a OSX with the built-in Python 2.5. I'm not very familiar with Tcl/Tk.
Attempt #1
If I could get to the underlying widgets, I could generate the clicks like in this question. However, looking at the dialog source, it appears to me that the Tcl call in lines 48-50 is blocking. Is this a correct assumption?
Attempt #2
I thought there might be a way using Tcl commands directly through root.tk.call. Since I'm on Python2, I think the underlying Tcl is a single call to tk_getOpenFile. Would I have to ensure the Tcl interpreter is threaded? Is there any Tcl/Tk command that can help me out here?
Attempt #3
I could implement the file selection from scratch using os.listdir etc. (Probably in a separate HTML page communicating back and forth with the server). It would be more than a little painful and hopefully avoidable.
Solution
Based on A. Rodas's answer below, I came up with the following:
import tkFileDialog
old_dialog = tkFileDialog.askopenfilename
try:
tkFileDialog.askopenfilename = lambda *args, **kw: filename
# First test dialog cancelled
filename = ''
method_that_calls_tk()
# run some assertions
# Next test a valid file name with valid contents
filename = self.VALID_FILENAME
method_that_calls_tk()
# run some assertions
# Now test a valid file name with invalid contents
filename = self.INVALID_CONTENTS_FILENAME
method_that_calls_tk()
# run some assertions
# Now test an invalid file name
filename = self.INVALID_FILENAME
method_that_calls_tk()
# run some assertions
finally:
tkFileDialog.askopenfilename = old_dialog
Unit testing of Tkinter code is not an easy issue. For instance, the IDLE does not have a proper test suite, even though it is part of the standard library. Since you mention that this is going to be the only use of Tkinter in your application, I'd suggest to make unit tests for the outcome of this code: the value of filename.
For instance, you can have a test for a .csv file, and another one for an incorrect file extension. Since tkFileDialog returns an empty string if it is closed by the user, add also a test where filename = ''.
import unittest
class TestFileDialog(unittest.TestCase):
def test_dialog_closed(self):
filename = ''
# ...
def test_incorrect_extension(self):
filename = '/path/to/another/filetype'
# ...
def test_csv_extension(self):
filename = '/path/to/correct/file.csv'
# ...
You could just patch the calls to tkinter:
patch tk.Tk() because most CI's will error because they don't have displays.
Also patch the file dialog so you can simulate return values and that it is being called with what you expect.
#patch('your_module.tk.Tk')
def test_your_stuff(self, Tk)
with #patch('your_module.tkFileDialog.askopenfilename') as file_dialog:
expected = 'expected return value'
assert expected = your_function_calling_file_dialog()
file_dialog.assert_called_once_with(whatever, you, expect, it, to, be, called, with)