diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 92c10df3e4e97..d54d29dcfacbc 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -175,6 +175,7 @@ jobs:
         pytest pandas/tests/computation/
         pytest pandas/tests/config/
         pytest pandas/tests/dtypes/
+        pytest pandas/tests/extension/
         pytest pandas/tests/generic/
         pytest pandas/tests/indexes/
         pytest pandas/tests/io/test_* -m "not slow and not clipboard"
diff --git a/pandas/core/internals/array_manager.py b/pandas/core/internals/array_manager.py
index 2177839eb34ce..4f196043b3129 100644
--- a/pandas/core/internals/array_manager.py
+++ b/pandas/core/internals/array_manager.py
@@ -684,7 +684,10 @@ def get_numeric_data(self, copy: bool = False) -> ArrayManager:
         copy : bool, default False
             Whether to copy the blocks
         """
-        return self._get_data_subset(lambda arr: is_numeric_dtype(arr.dtype))
+        return self._get_data_subset(
+            lambda arr: is_numeric_dtype(arr.dtype)
+            or getattr(arr.dtype, "_is_numeric", False)
+        )
 
     def copy(self: T, deep=True) -> T:
         """
diff --git a/pandas/tests/extension/base/casting.py b/pandas/tests/extension/base/casting.py
index 0b79a5368a542..7c5ef5b3b27d3 100644
--- a/pandas/tests/extension/base/casting.py
+++ b/pandas/tests/extension/base/casting.py
@@ -12,14 +12,21 @@ class BaseCastingTests(BaseExtensionTests):
     def test_astype_object_series(self, all_data):
         ser = pd.Series(all_data, name="A")
         result = ser.astype(object)
-        assert isinstance(result._mgr.blocks[0], ObjectBlock)
+        assert result.dtype == np.dtype(object)
+        if hasattr(result._mgr, "blocks"):
+            assert isinstance(result._mgr.blocks[0], ObjectBlock)
+        assert isinstance(result._mgr.array, np.ndarray)
+        assert result._mgr.array.dtype == np.dtype(object)
 
     def test_astype_object_frame(self, all_data):
         df = pd.DataFrame({"A": all_data})
 
         result = df.astype(object)
-        blk = result._data.blocks[0]
-        assert isinstance(blk, ObjectBlock), type(blk)
+        if hasattr(result._mgr, "blocks"):
+            blk = result._data.blocks[0]
+            assert isinstance(blk, ObjectBlock), type(blk)
+        assert isinstance(result._mgr.arrays[0], np.ndarray)
+        assert result._mgr.arrays[0].dtype == np.dtype(object)
 
         # FIXME: these currently fail; dont leave commented-out
         # check that we can compare the dtypes
diff --git a/pandas/tests/extension/base/constructors.py b/pandas/tests/extension/base/constructors.py
index 6f0d8d16a0224..e2323620daa0e 100644
--- a/pandas/tests/extension/base/constructors.py
+++ b/pandas/tests/extension/base/constructors.py
@@ -2,6 +2,7 @@
 import pytest
 
 import pandas as pd
+from pandas.api.extensions import ExtensionArray
 from pandas.core.internals import ExtensionBlock
 from pandas.tests.extension.base.base import BaseExtensionTests
 
@@ -24,13 +25,15 @@ def test_series_constructor(self, data):
         result = pd.Series(data)
         assert result.dtype == data.dtype
         assert len(result) == len(data)
-        assert isinstance(result._mgr.blocks[0], ExtensionBlock)
-        assert result._mgr.blocks[0].values is data
+        if hasattr(result._mgr, "blocks"):
+            assert isinstance(result._mgr.blocks[0], ExtensionBlock)
+        assert result._mgr.array is data
 
         # Series[EA] is unboxed / boxed correctly
         result2 = pd.Series(result)
         assert result2.dtype == data.dtype
-        assert isinstance(result2._mgr.blocks[0], ExtensionBlock)
+        if hasattr(result._mgr, "blocks"):
+            assert isinstance(result2._mgr.blocks[0], ExtensionBlock)
 
     def test_series_constructor_no_data_with_index(self, dtype, na_value):
         result = pd.Series(index=[1, 2, 3], dtype=dtype)
@@ -64,13 +67,17 @@ def test_dataframe_constructor_from_dict(self, data, from_series):
         result = pd.DataFrame({"A": data})
         assert result.dtypes["A"] == data.dtype
         assert result.shape == (len(data), 1)
-        assert isinstance(result._mgr.blocks[0], ExtensionBlock)
+        if hasattr(result._mgr, "blocks"):
+            assert isinstance(result._mgr.blocks[0], ExtensionBlock)
+        assert isinstance(result._mgr.arrays[0], ExtensionArray)
 
     def test_dataframe_from_series(self, data):
         result = pd.DataFrame(pd.Series(data))
         assert result.dtypes[0] == data.dtype
         assert result.shape == (len(data), 1)
-        assert isinstance(result._mgr.blocks[0], ExtensionBlock)
+        if hasattr(result._mgr, "blocks"):
+            assert isinstance(result._mgr.blocks[0], ExtensionBlock)
+        assert isinstance(result._mgr.arrays[0], ExtensionArray)
 
     def test_series_given_mismatched_index_raises(self, data):
         msg = r"Length of values \(3\) does not match length of index \(5\)"
diff --git a/pandas/tests/extension/base/getitem.py b/pandas/tests/extension/base/getitem.py
index 971da37c105bd..96833a2e49fa1 100644
--- a/pandas/tests/extension/base/getitem.py
+++ b/pandas/tests/extension/base/getitem.py
@@ -408,7 +408,10 @@ def test_loc_len1(self, data):
         # see GH-27785 take_nd with indexer of len 1 resulting in wrong ndim
         df = pd.DataFrame({"A": data})
         res = df.loc[[0], "A"]
-        assert res._mgr._block.ndim == 1
+        assert res.ndim == 1
+        assert res._mgr.arrays[0].ndim == 1
+        if hasattr(res._mgr, "blocks"):
+            assert res._mgr._block.ndim == 1
 
     def test_item(self, data):
         # https://github.com/pandas-dev/pandas/pull/30175
diff --git a/pandas/tests/extension/base/interface.py b/pandas/tests/extension/base/interface.py
index 5bf26e2ca476e..f51f9f732bace 100644
--- a/pandas/tests/extension/base/interface.py
+++ b/pandas/tests/extension/base/interface.py
@@ -81,7 +81,8 @@ def test_no_values_attribute(self, data):
 
     def test_is_numeric_honored(self, data):
         result = pd.Series(data)
-        assert result._mgr.blocks[0].is_numeric is data.dtype._is_numeric
+        if hasattr(result._mgr, "blocks"):
+            assert result._mgr.blocks[0].is_numeric is data.dtype._is_numeric
 
     def test_isna_extension_array(self, data_missing):
         # If your `isna` returns an ExtensionArray, you must also implement
diff --git a/pandas/tests/extension/base/reshaping.py b/pandas/tests/extension/base/reshaping.py
index 18f6084f989dc..5a2d928eea744 100644
--- a/pandas/tests/extension/base/reshaping.py
+++ b/pandas/tests/extension/base/reshaping.py
@@ -3,7 +3,10 @@
 import numpy as np
 import pytest
 
+import pandas.util._test_decorators as td
+
 import pandas as pd
+from pandas.api.extensions import ExtensionArray
 from pandas.core.internals import ExtensionBlock
 from pandas.tests.extension.base.base import BaseExtensionTests
 
@@ -26,7 +29,9 @@ def test_concat(self, data, in_frame):
             dtype = result.dtype
 
         assert dtype == data.dtype
-        assert isinstance(result._mgr.blocks[0], ExtensionBlock)
+        if hasattr(result._mgr, "blocks"):
+            assert isinstance(result._mgr.blocks[0], ExtensionBlock)
+        assert isinstance(result._mgr.arrays[0], ExtensionArray)
 
     @pytest.mark.parametrize("in_frame", [True, False])
     def test_concat_all_na_block(self, data_missing, in_frame):
@@ -106,6 +111,7 @@ def test_concat_extension_arrays_copy_false(self, data, na_value):
         result = pd.concat([df1, df2], axis=1, copy=False)
         self.assert_frame_equal(result, expected)
 
+    @td.skip_array_manager_not_yet_implemented  # TODO(ArrayManager) concat reindex
     def test_concat_with_reindex(self, data):
         # GH-33027
         a = pd.DataFrame({"a": data[:5]})
diff --git a/pandas/tests/extension/test_external_block.py b/pandas/tests/extension/test_external_block.py
index 9360294f5a3f7..ee46d13055010 100644
--- a/pandas/tests/extension/test_external_block.py
+++ b/pandas/tests/extension/test_external_block.py
@@ -2,11 +2,14 @@
 import pytest
 
 from pandas._libs.internals import BlockPlacement
+import pandas.util._test_decorators as td
 
 import pandas as pd
 from pandas.core.internals import BlockManager
 from pandas.core.internals.blocks import ExtensionBlock
 
+pytestmark = td.skip_array_manager_invalid_test
+
 
 class CustomBlock(ExtensionBlock):
 
diff --git a/pandas/tests/extension/test_numpy.py b/pandas/tests/extension/test_numpy.py
index bc1f499a70aa0..051871513a14e 100644
--- a/pandas/tests/extension/test_numpy.py
+++ b/pandas/tests/extension/test_numpy.py
@@ -16,6 +16,8 @@
 import numpy as np
 import pytest
 
+import pandas.util._test_decorators as td
+
 from pandas.core.dtypes.dtypes import (
     ExtensionDtype,
     PandasDtype,
@@ -28,6 +30,9 @@
 from pandas.core.internals import managers
 from pandas.tests.extension import base
 
+# TODO(ArrayManager) PandasArray
+pytestmark = td.skip_array_manager_not_yet_implemented
+
 
 def _extract_array_patched(obj):
     if isinstance(obj, (pd.Index, pd.Series)):
diff --git a/pandas/tests/extension/test_sparse.py b/pandas/tests/extension/test_sparse.py
index b8e042f0599f7..0613c727dec98 100644
--- a/pandas/tests/extension/test_sparse.py
+++ b/pandas/tests/extension/test_sparse.py
@@ -290,7 +290,8 @@ def test_fillna_copy_frame(self, data_missing):
         filled_val = df.iloc[0, 0]
         result = df.fillna(filled_val)
 
-        assert df.values.base is not result.values.base
+        if hasattr(df._mgr, "blocks"):
+            assert df.values.base is not result.values.base
         assert df.A._values.to_dense() is arr.to_dense()
 
     def test_fillna_copy_series(self, data_missing):
@@ -362,18 +363,19 @@ def test_equals(self, data, na_value, as_series, box):
 class TestCasting(BaseSparseTests, base.BaseCastingTests):
     def test_astype_object_series(self, all_data):
         # Unlike the base class, we do not expect the resulting Block
-        #  to be ObjectBlock
+        #  to be ObjectBlock / resulting array to be np.dtype("object")
         ser = pd.Series(all_data, name="A")
         result = ser.astype(object)
-        assert is_object_dtype(result._data.blocks[0].dtype)
+        assert is_object_dtype(result.dtype)
+        assert is_object_dtype(result._mgr.array.dtype)
 
     def test_astype_object_frame(self, all_data):
         # Unlike the base class, we do not expect the resulting Block
-        #  to be ObjectBlock
+        #  to be ObjectBlock / resulting array to be np.dtype("object")
         df = pd.DataFrame({"A": all_data})
 
         result = df.astype(object)
-        assert is_object_dtype(result._data.blocks[0].dtype)
+        assert is_object_dtype(result._mgr.arrays[0].dtype)
 
         # FIXME: these currently fail; dont leave commented-out
         # check that we can compare the dtypes