diff --git a/xarray/tests/test_dataarray.py b/xarray/tests/test_dataarray.py
index ece2ddf8144..659c7c168a5 100644
--- a/xarray/tests/test_dataarray.py
+++ b/xarray/tests/test_dataarray.py
@@ -110,13 +110,14 @@ def test_repr(self) -> None:
         assert expected == repr(data_array)
 
     def test_repr_multiindex(self) -> None:
+        obj_size = np.dtype("O").itemsize
         expected = dedent(
-            """\
+            f"""\
             <xarray.DataArray (x: 4)> Size: 32B
             array([0, 1, 2, 3], dtype=uint64)
             Coordinates:
-              * x        (x) object 32B MultiIndex
-              * level_1  (x) object 32B 'a' 'a' 'b' 'b'
+              * x        (x) object {4 * obj_size}B MultiIndex
+              * level_1  (x) object {4 * obj_size}B 'a' 'a' 'b' 'b'
               * level_2  (x) int64 32B 1 2 1 2"""
         )
         assert expected == repr(self.mda)
@@ -129,15 +130,16 @@ def test_repr_multiindex_long(self) -> None:
         mda_long = DataArray(
             list(range(32)), coords={"x": mindex_long}, dims="x"
         ).astype(np.uint64)
+        obj_size = np.dtype("O").itemsize
         expected = dedent(
-            """\
+            f"""\
             <xarray.DataArray (x: 32)> Size: 256B
             array([ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16,
                    17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31],
                   dtype=uint64)
             Coordinates:
-              * x        (x) object 256B MultiIndex
-              * level_1  (x) object 256B 'a' 'a' 'a' 'a' 'a' 'a' ... 'd' 'd' 'd' 'd' 'd' 'd'
+              * x        (x) object {32 * obj_size}B MultiIndex
+              * level_1  (x) object {32 * obj_size}B 'a' 'a' 'a' 'a' 'a' 'a' ... 'd' 'd' 'd' 'd' 'd' 'd'
               * level_2  (x) int64 256B 1 2 3 4 5 6 7 8 1 2 3 4 ... 5 6 7 8 1 2 3 4 5 6 7 8"""
         )
         assert expected == repr(mda_long)
diff --git a/xarray/tests/test_dataset.py b/xarray/tests/test_dataset.py
index 81b27da8d5f..f6829861776 100644
--- a/xarray/tests/test_dataset.py
+++ b/xarray/tests/test_dataset.py
@@ -335,13 +335,14 @@ def test_repr(self) -> None:
 
     def test_repr_multiindex(self) -> None:
         data = create_test_multiindex()
+        obj_size = np.dtype("O").itemsize
         expected = dedent(
-            """\
-            <xarray.Dataset> Size: 96B
+            f"""\
+            <xarray.Dataset> Size: {8 * obj_size + 32}B
             Dimensions:  (x: 4)
             Coordinates:
-              * x        (x) object 32B MultiIndex
-              * level_1  (x) object 32B 'a' 'a' 'b' 'b'
+              * x        (x) object {4 * obj_size}B MultiIndex
+              * level_1  (x) object {4 * obj_size}B 'a' 'a' 'b' 'b'
               * level_2  (x) int64 32B 1 2 1 2
             Data variables:
                 *empty*"""
@@ -357,12 +358,12 @@ def test_repr_multiindex(self) -> None:
         midx_coords = Coordinates.from_pandas_multiindex(midx, "x")
         data = Dataset({}, midx_coords)
         expected = dedent(
-            """\
-            <xarray.Dataset> Size: 96B
+            f"""\
+            <xarray.Dataset> Size: {8 * obj_size + 32}B
             Dimensions:                  (x: 4)
             Coordinates:
-              * x                        (x) object 32B MultiIndex
-              * a_quite_long_level_name  (x) object 32B 'a' 'a' 'b' 'b'
+              * x                        (x) object {4 * obj_size}B MultiIndex
+              * a_quite_long_level_name  (x) object {4 * obj_size}B 'a' 'a' 'b' 'b'
               * level_2                  (x) int64 32B 1 2 1 2
             Data variables:
                 *empty*"""
diff --git a/xarray/tests/test_formatting.py b/xarray/tests/test_formatting.py
index 2c40ac88f98..b9d5f401a4a 100644
--- a/xarray/tests/test_formatting.py
+++ b/xarray/tests/test_formatting.py
@@ -12,8 +12,6 @@
 from xarray.core.datatree import DataTree  # TODO: Remove when can do xr.DataTree
 from xarray.tests import requires_cftime, requires_dask, requires_netCDF4
 
-ON_WINDOWS = sys.platform == "win32"
-
 
 class TestFormatting:
     def test_get_indexer_at_least_n_items(self) -> None:
@@ -1071,74 +1069,34 @@ def test_array_repr_dtypes():
         """.strip()
     assert actual == expected
 
-
-@pytest.mark.skipif(
-    ON_WINDOWS,
-    reason="Default numpy's dtypes vary according to OS",
-)
-def test_array_repr_dtypes_unix() -> None:
-
     # Signed integer dtypes
 
-    ds = xr.DataArray(np.array([0]), dims="x")
+    array = np.array([0])
+    ds = xr.DataArray(array, dims="x")
     actual = repr(ds)
-    expected = """
-<xarray.DataArray (x: 1)> Size: 8B
-array([0])
+    expected = f"""
+<xarray.DataArray (x: 1)> Size: {array.dtype.itemsize}B
+{repr(array)}
 Dimensions without coordinates: x
         """.strip()
     assert actual == expected
 
-    ds = xr.DataArray(np.array([0], dtype="int32"), dims="x")
+    array = np.array([0], dtype="int32")
+    ds = xr.DataArray(array, dims="x")
     actual = repr(ds)
-    expected = """
+    expected = f"""
 <xarray.DataArray (x: 1)> Size: 4B
-array([0], dtype=int32)
+{repr(array)}
 Dimensions without coordinates: x
         """.strip()
     assert actual == expected
 
-    ds = xr.DataArray(np.array([0], dtype="int64"), dims="x")
+    array = np.array([0], dtype="int64")
+    ds = xr.DataArray(array, dims="x")
     actual = repr(ds)
-    expected = """
-<xarray.DataArray (x: 1)> Size: 8B
-array([0])
-Dimensions without coordinates: x
-        """.strip()
-    assert actual == expected
-
-
-@pytest.mark.skipif(
-    not ON_WINDOWS,
-    reason="Default numpy's dtypes vary according to OS",
-)
-def test_array_repr_dtypes_on_windows() -> None:
-
-    # Integer dtypes
-
-    ds = xr.DataArray(np.array([0]), dims="x")
-    actual = repr(ds)
-    expected = """
-<xarray.DataArray (x: 1)> Size: 4B
-array([0])
-Dimensions without coordinates: x
-        """.strip()
-    assert actual == expected
-
-    ds = xr.DataArray(np.array([0], dtype="int32"), dims="x")
-    actual = repr(ds)
-    expected = """
-<xarray.DataArray (x: 1)> Size: 4B
-array([0])
-Dimensions without coordinates: x
-        """.strip()
-    assert actual == expected
-
-    ds = xr.DataArray(np.array([0], dtype="int64"), dims="x")
-    actual = repr(ds)
-    expected = """
+    expected = f"""
 <xarray.DataArray (x: 1)> Size: 8B
-array([0], dtype=int64)
+{repr(array)}
 Dimensions without coordinates: x
         """.strip()
     assert actual == expected