TypeError: Surface.write_to_png takes one argument which must be a filename, file object, or a file-like object which has a "write" method (like StringIO)

[shoaibmalek21]

============================================================ test session starts =============================================================
platform linux2 -- Python 2.7.17, pytest-3.3.2, py-1.5.2, pluggy-0.6.0
rootdir: /home/shoaib/pcb_development/pcb-tools, inifile:
collected 330 items

gerber/tests/test_am_statements.py .............................................. [ 13%]
gerber/tests/test_cairo_backend.py FFF. [ 15%]
gerber/tests/test_cam.py .......... [ 18%]
gerber/tests/test_common.py ... [ 19%]
gerber/tests/test_excellon.py ............................ [ 27%]
gerber/tests/test_excellon_statements.py ............................................................ [ 45%]
gerber/tests/test_gerber_statements.py .......................................................................... [ 68%]
gerber/tests/test_ipc356.py ....... [ 70%]
gerber/tests/test_layers.py ....... [ 72%]
gerber/tests/test_primitives.py ............................................................................ [ 95%]
gerber/tests/test_rs274x.py ..... [ 96%]
gerber/tests/test_rs274x_backend.py . [ 97%]
gerber/tests/test_utils.py ......... [100%]

================================================================== FAILURES ==================================================================
______________________________________________________ test_render_overlapping_touching ______________________________________________________

def test_render_overlapping_touching():
    """Umaco example of D02 staring a second contour"""
    _test_render(
        "resources/example_overlapping_touching.gbr",

      "golden/example_overlapping_touching.png",

    )

gerber/tests/test_cairo_backend.py:82:

---

gerber/tests/test_cairo_backend.py:224: in _test_render
actual_bytes = ctx.dump(None)

---

self = <gerber.render.cairo_backend.GerberCairoContext object at 0x7f418598a950>, filename = None, verbose = False

def dump(self, filename=None, verbose=False):
    """ Save image as `filename`
        """
    try:
        is_svg = os.path.splitext(filename.lower())[1] == '.svg'
    except:
        is_svg = False
    if verbose:
        print('[Render]: Writing image to {}'.format(filename))
    if is_svg:
        self.surface.finish()
        self.surface_buffer.flush()
        with open(filename, "wb") as f:
            self.surface_buffer.seek(0)
            f.write(self.surface_buffer.read())
            f.flush()
    else:

      return self.surface.write_to_png(filename)

E TypeError: Surface.write_to_png takes one argument which must be a filename, file object, or a file-like object which has a "write" method (like StringIO)

gerber/render/cairo_backend.py:150: TypeError
______________________________________________________ test_render_overlapping_contour _______________________________________________________

def test_render_overlapping_contour():
    """Umaco example of D02 staring a second contour"""
    _test_render(
        "resources/example_overlapping_contour.gbr",

      "golden/example_overlapping_contour.png",

    )

gerber/tests/test_cairo_backend.py:90:

---

gerber/tests/test_cairo_backend.py:224: in _test_render
actual_bytes = ctx.dump(None)

---

self = <gerber.render.cairo_backend.GerberCairoContext object at 0x7f41859b8690>, filename = None, verbose = False

def dump(self, filename=None, verbose=False):
    """ Save image as `filename`
        """
    try:
        is_svg = os.path.splitext(filename.lower())[1] == '.svg'
    except:
        is_svg = False
    if verbose:
        print('[Render]: Writing image to {}'.format(filename))
    if is_svg:
        self.surface.finish()
        self.surface_buffer.flush()
        with open(filename, "wb") as f:
            self.surface_buffer.seek(0)
            f.write(self.surface_buffer.read())
            f.flush()
    else:

      return self.surface.write_to_png(filename)

E TypeError: Surface.write_to_png takes one argument which must be a filename, file object, or a file-like object which has a "write" method (like StringIO)

gerber/render/cairo_backend.py:150: TypeError
_________________________________________________________ test_render_cutin_multiple _________________________________________________________

def test_render_cutin_multiple():
    """Umaco example of a region with multiple cutins"""

    _test_render(

      "resources/example_cutin_multiple.gbr", "golden/example_cutin_multiple.png"

    )

gerber/tests/test_cairo_backend.py:135:

---

gerber/tests/test_cairo_backend.py:224: in _test_render
actual_bytes = ctx.dump(None)

---

self = <gerber.render.cairo_backend.GerberCairoContext object at 0x7f41859534d0>, filename = None, verbose = False

def dump(self, filename=None, verbose=False):
    """ Save image as `filename`
        """
    try:
        is_svg = os.path.splitext(filename.lower())[1] == '.svg'
    except:
        is_svg = False
    if verbose:
        print('[Render]: Writing image to {}'.format(filename))
    if is_svg:
        self.surface.finish()
        self.surface_buffer.flush()
        with open(filename, "wb") as f:
            self.surface_buffer.seek(0)
            f.write(self.surface_buffer.read())
            f.flush()
    else:

      return self.surface.write_to_png(filename)

E TypeError: Surface.write_to_png takes one argument which must be a filename, file object, or a file-like object which has a "write" method (like StringIO)

gerber/render/cairo_backend.py:150: TypeError
============================================================== warnings summary ==============================================================
gerber/tests/test_ipc356.py::TestRecord
cannot collect test class 'TestRecord' because it has a init constructor

gerber/tests/test_primitives.py::TestRecord
cannot collect test class 'TestRecord' because it has a init constructor

-- Docs: http://doc.pytest.org/en/latest/warnings.html
============================================== 3 failed, 327 passed, 2 warnings in 7.76 seconds =============================================