diff --git a/lib/matplotlib/tests/test_backend_bases.py b/lib/matplotlib/tests/test_backend_bases.py
index 77f6bebd262b..f157a1e5a98a 100644
--- a/lib/matplotlib/tests/test_backend_bases.py
+++ b/lib/matplotlib/tests/test_backend_bases.py
@@ -59,12 +59,8 @@ def test_canvas_ctor():
     assert isinstance(FigureCanvasBase().figure, Figure)
 
 
-def test_get_default_filename(tmpdir):
-    plt.rcParams['savefig.directory'] = str(tmpdir)
-    fig = plt.figure()
-    canvas = FigureCanvasBase(fig)
-    filename = canvas.get_default_filename()
-    assert filename == 'image.png'
+def test_get_default_filename():
+    assert plt.figure().canvas.get_default_filename() == 'image.png'
 
 
 def test_canvas_change():
diff --git a/lib/matplotlib/tests/test_backend_pdf.py b/lib/matplotlib/tests/test_backend_pdf.py
index 2db3a8d7efc0..31d50ac1302f 100644
--- a/lib/matplotlib/tests/test_backend_pdf.py
+++ b/lib/matplotlib/tests/test_backend_pdf.py
@@ -315,16 +315,11 @@ def test_pdf_eps_savefig_when_color_is_none(fig_test, fig_ref):
 
 
 @needs_usetex
-def test_failing_latex(tmpdir):
+def test_failing_latex():
     """Test failing latex subprocess call"""
-    path = str(tmpdir.join("tmpoutput.pdf"))
-
-    rcParams['text.usetex'] = True
-
-    # This fails with "Double subscript"
-    plt.xlabel("$22_2_2$")
+    plt.xlabel("$22_2_2$", usetex=True)  # This fails with "Double subscript"
     with pytest.raises(RuntimeError):
-        plt.savefig(path)
+        plt.savefig(io.BytesIO(), format="pdf")
 
 
 def test_empty_rasterized():
diff --git a/lib/matplotlib/tests/test_backend_pgf.py b/lib/matplotlib/tests/test_backend_pgf.py
index e3d29a9c434c..dde543562d9d 100644
--- a/lib/matplotlib/tests/test_backend_pgf.py
+++ b/lib/matplotlib/tests/test_backend_pgf.py
@@ -312,11 +312,10 @@ def test_tex_restart_after_error():
 
 
 @needs_xelatex
-def test_bbox_inches_tight(tmpdir):
+def test_bbox_inches_tight():
     fig, ax = plt.subplots()
     ax.imshow([[0, 1], [2, 3]])
-    fig.savefig(os.path.join(tmpdir, "test.pdf"), backend="pgf",
-                bbox_inches="tight")
+    fig.savefig(BytesIO(), format="pdf", backend="pgf", bbox_inches="tight")
 
 
 @needs_xelatex