prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  pytest is now a hidden hard dependency
  <!--To help us understand and resolve your issue, please fill out the form to
  the best of your ability.-->
  <!--You can feel free to delete the sections that do not apply.-->
  
  ### Bug report
  
  We now import `pytest` directly in `yt/testing.py`, but `pytest` is not yet listed as a hard dependency. This will cause a `ModuleNotFoundError` to be raised after installing yt until you install pytest manually.
  
  I'm opening an issue rather than a PR because I don't know whether people would prefer to put the `pytest` import in a try block or make it a dependency.
  
  </issue>
  <code>
  [start of yt/__init__.py]
  1 """
  2 yt is a toolkit for analyzing and visualizing volumetric data.
  3 
  4 * Website: https://yt-project.org
  5 * Documentation: https://yt-project.org/doc
  6 * Data hub: https://girder.hub.yt
  7 * Contribute: https://github.com/yt-project/yt
  8 
  9 """
  10 __version__ = "4.1.dev0"
  11 
  12 import yt.units as units
  13 import yt.utilities.physical_constants as physical_constants
  14 from yt.data_objects.api import (
  15     DatasetSeries,
  16     ImageArray,
  17     ParticleProfile,
  18     Profile1D,
  19     Profile2D,
  20     Profile3D,
  21     add_particle_filter,
  22     create_profile,
  23     particle_filter,
  24 )
  25 from yt.fields.api import (
  26     DerivedField,
  27     FieldDetector,
  28     FieldInfoContainer,
  29     ValidateDataField,
  30     ValidateGridType,
  31     ValidateParameter,
  32     ValidateProperty,
  33     ValidateSpatial,
  34     add_field,
  35     add_xray_emissivity_field,
  36     derived_field,
  37     field_plugins,
  38 )
  39 from yt.frontends.api import _frontend_container
  40 from yt.funcs import (
  41     enable_plugins,
  42     get_memory_usage,
  43     get_pbar,
  44     get_version_stack,
  45     get_yt_version,
  46     insert_ipython,
  47     is_root,
  48     is_sequence,
  49     memory_checker,
  50     only_on_root,
  51     parallel_profile,
  52     print_tb,
  53     rootonly,
  54     toggle_interactivity,
  55 )
  56 from yt.units import (
  57     YTArray,
  58     YTQuantity,
  59     display_ytarray,
  60     loadtxt,
  61     savetxt,
  62     uconcatenate,
  63     ucross,
  64     udot,
  65     uhstack,
  66     uintersect1d,
  67     unorm,
  68     ustack,
  69     uunion1d,
  70     uvstack,
  71 )
  72 from yt.units.unit_object import define_unit  # type: ignore
  73 from yt.utilities.logger import set_log_level, ytLogger as mylog
  74 
  75 frontends = _frontend_container()
  76 
  77 import yt.visualization.volume_rendering.api as volume_rendering
  78 from yt.frontends.stream.api import hexahedral_connectivity
  79 from yt.frontends.ytdata.api import save_as_dataset
  80 from yt.loaders import (
  81     load,
  82     load_amr_grids,
  83     load_archive,
  84     load_hexahedral_mesh,
  85     load_octree,
  86     load_particles,
  87     load_sample,
  88     load_simulation,
  89     load_uniform_grid,
  90     load_unstructured_mesh,
  91 )
  92 from yt.testing import run_nose
  93 from yt.units.unit_systems import UnitSystem, unit_system_registry  # type: ignore
  94 
  95 # Import some helpful math utilities
  96 from yt.utilities.math_utils import ortho_find, periodic_position, quartiles
  97 from yt.utilities.parallel_tools.parallel_analysis_interface import (
  98     communication_system,
  99     enable_parallelism,
  100     parallel_objects,
  101 )
  102 
  103 # Now individual component imports from the visualization API
  104 from yt.visualization.api import (
  105     AxisAlignedProjectionPlot,
  106     AxisAlignedSlicePlot,
  107     FITSImageData,
  108     FITSOffAxisProjection,
  109     FITSOffAxisSlice,
  110     FITSParticleProjection,
  111     FITSProjection,
  112     FITSSlice,
  113     FixedResolutionBuffer,
  114     LineBuffer,
  115     LinePlot,
  116     OffAxisProjectionPlot,
  117     OffAxisSlicePlot,
  118     ParticleImageBuffer,
  119     ParticlePhasePlot,
  120     ParticlePlot,
  121     ParticleProjectionPlot,
  122     PhasePlot,
  123     ProfilePlot,
  124     ProjectionPlot,
  125     SlicePlot,
  126     add_colormap,
  127     apply_colormap,
  128     make_colormap,
  129     plot_2d,
  130     scale_image,
  131     show_colormaps,
  132     write_bitmap,
  133     write_image,
  134     write_projection,
  135 )
  136 from yt.visualization.volume_rendering.api import (
  137     ColorTransferFunction,
  138     TransferFunction,
  139     create_scene,
  140     off_axis_projection,
  141     volume_render,
  142 )
  143 
  144 #    TransferFunctionHelper, MultiVariateTransferFunction
  145 #    off_axis_projection
  146
  [end of yt/__init__.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/yt/__init__.py b/yt/__init__.py
  --- a/yt/__init__.py
  +++ b/yt/__init__.py
  @@ -89,7 +89,17 @@
       load_uniform_grid,
       load_unstructured_mesh,
   )
  -from yt.testing import run_nose
  +
  +
  +def run_nose(*args, **kwargs):
  +    # we hide this function behind a closure so we
  +    # don't make pytest a hard dependency for end users
  +    # see https://github.com/yt-project/yt/issues/3771
  +    from yt.testing import run_nose
  +
  +    return run_nose(*args, **kwargs)
  +
  +
   from yt.units.unit_systems import UnitSystem, unit_system_registry  # type: ignore
   
   # Import some helpful math utilities
  
verification_info: {"golden_diff": "diff --git a/yt/__init__.py b/yt/__init__.py\n--- a/yt/__init__.py\n+++ b/yt/__init__.py\n@@ -89,7 +89,17 @@\n     load_uniform_grid,\n     load_unstructured_mesh,\n )\n-from yt.testing import run_nose\n+\n+\n+def run_nose(*args, **kwargs):\n+    # we hide this function behind a closure so we\n+    # don't make pytest a hard dependency for end users\n+    # see https://github.com/yt-project/yt/issues/3771\n+    from yt.testing import run_nose\n+\n+    return run_nose(*args, **kwargs)\n+\n+\n from yt.units.unit_systems import UnitSystem, unit_system_registry  # type: ignore\n \n # Import some helpful math utilities\n", "issue": "pytest is now a hidden hard dependency\n<!--To help us understand and resolve your issue, please fill out the form to\r\nthe best of your ability.-->\r\n<!--You can feel free to delete the sections that do not apply.-->\r\n\r\n### Bug report\r\n\r\nWe now import `pytest` directly in `yt/testing.py`, but `pytest` is not yet listed as a hard dependency. This will cause a `ModuleNotFoundError` to be raised after installing yt until you install pytest manually.\r\n\r\nI'm opening an issue rather than a PR because I don't know whether people would prefer to put the `pytest` import in a try block or make it a dependency.\n", "before_files": [{"content": "\"\"\"\nyt is a toolkit for analyzing and visualizing volumetric data.\n\n* Website: https://yt-project.org\n* Documentation: https://yt-project.org/doc\n* Data hub: https://girder.hub.yt\n* Contribute: https://github.com/yt-project/yt\n\n\"\"\"\n__version__ = \"4.1.dev0\"\n\nimport yt.units as units\nimport yt.utilities.physical_constants as physical_constants\nfrom yt.data_objects.api import (\n    DatasetSeries,\n    ImageArray,\n    ParticleProfile,\n    Profile1D,\n    Profile2D,\n    Profile3D,\n    add_particle_filter,\n    create_profile,\n    particle_filter,\n)\nfrom yt.fields.api import (\n    DerivedField,\n    FieldDetector,\n    FieldInfoContainer,\n    ValidateDataField,\n    ValidateGridType,\n    ValidateParameter,\n    ValidateProperty,\n    ValidateSpatial,\n    add_field,\n    add_xray_emissivity_field,\n    derived_field,\n    field_plugins,\n)\nfrom yt.frontends.api import _frontend_container\nfrom yt.funcs import (\n    enable_plugins,\n    get_memory_usage,\n    get_pbar,\n    get_version_stack,\n    get_yt_version,\n    insert_ipython,\n    is_root,\n    is_sequence,\n    memory_checker,\n    only_on_root,\n    parallel_profile,\n    print_tb,\n    rootonly,\n    toggle_interactivity,\n)\nfrom yt.units import (\n    YTArray,\n    YTQuantity,\n    display_ytarray,\n    loadtxt,\n    savetxt,\n    uconcatenate,\n    ucross,\n    udot,\n    uhstack,\n    uintersect1d,\n    unorm,\n    ustack,\n    uunion1d,\n    uvstack,\n)\nfrom yt.units.unit_object import define_unit  # type: ignore\nfrom yt.utilities.logger import set_log_level, ytLogger as mylog\n\nfrontends = _frontend_container()\n\nimport yt.visualization.volume_rendering.api as volume_rendering\nfrom yt.frontends.stream.api import hexahedral_connectivity\nfrom yt.frontends.ytdata.api import save_as_dataset\nfrom yt.loaders import (\n    load,\n    load_amr_grids,\n    load_archive,\n    load_hexahedral_mesh,\n    load_octree,\n    load_particles,\n    load_sample,\n    load_simulation,\n    load_uniform_grid,\n    load_unstructured_mesh,\n)\nfrom yt.testing import run_nose\nfrom yt.units.unit_systems import UnitSystem, unit_system_registry  # type: ignore\n\n# Import some helpful math utilities\nfrom yt.utilities.math_utils import ortho_find, periodic_position, quartiles\nfrom yt.utilities.parallel_tools.parallel_analysis_interface import (\n    communication_system,\n    enable_parallelism,\n    parallel_objects,\n)\n\n# Now individual component imports from the visualization API\nfrom yt.visualization.api import (\n    AxisAlignedProjectionPlot,\n    AxisAlignedSlicePlot,\n    FITSImageData,\n    FITSOffAxisProjection,\n    FITSOffAxisSlice,\n    FITSParticleProjection,\n    FITSProjection,\n    FITSSlice,\n    FixedResolutionBuffer,\n    LineBuffer,\n    LinePlot,\n    OffAxisProjectionPlot,\n    OffAxisSlicePlot,\n    ParticleImageBuffer,\n    ParticlePhasePlot,\n    ParticlePlot,\n    ParticleProjectionPlot,\n    PhasePlot,\n    ProfilePlot,\n    ProjectionPlot,\n    SlicePlot,\n    add_colormap,\n    apply_colormap,\n    make_colormap,\n    plot_2d,\n    scale_image,\n    show_colormaps,\n    write_bitmap,\n    write_image,\n    write_projection,\n)\nfrom yt.visualization.volume_rendering.api import (\n    ColorTransferFunction,\n    TransferFunction,\n    create_scene,\n    off_axis_projection,\n    volume_render,\n)\n\n#    TransferFunctionHelper, MultiVariateTransferFunction\n#    off_axis_projection\n", "path": "yt/__init__.py"}]}