diff --git a/src/zarr/abc/codec.py b/src/zarr/abc/codec.py
index d5c995d2ca..43b92e13df 100644
--- a/src/zarr/abc/codec.py
+++ b/src/zarr/abc/codec.py
@@ -138,7 +138,7 @@ def validate(
         """
 
     async def _decode_single(self, chunk_data: CodecOutput, chunk_spec: ArraySpec) -> CodecInput:
-        raise NotImplementedError
+        raise NotImplementedError  # pragma: no cover
 
     async def decode(
         self,
@@ -161,7 +161,7 @@ async def decode(
     async def _encode_single(
         self, chunk_data: CodecInput, chunk_spec: ArraySpec
     ) -> CodecOutput | None:
-        raise NotImplementedError
+        raise NotImplementedError  # pragma: no cover
 
     async def encode(
         self,
@@ -242,7 +242,7 @@ async def _encode_partial_single(
         selection: SelectorTuple,
         chunk_spec: ArraySpec,
     ) -> None:
-        raise NotImplementedError
+        raise NotImplementedError  # pragma: no cover
 
     async def encode_partial(
         self,
diff --git a/tests/test_api/test_asynchronous.py b/tests/test_api/test_asynchronous.py
new file mode 100644
index 0000000000..35c803ad25
--- /dev/null
+++ b/tests/test_api/test_asynchronous.py
@@ -0,0 +1,105 @@
+from __future__ import annotations
+
+import json
+from dataclasses import dataclass
+from typing import TYPE_CHECKING
+
+import numpy as np
+import pytest
+
+from zarr import create_array
+from zarr.api.asynchronous import _get_shape_chunks, _like_args, open
+from zarr.core.buffer.core import default_buffer_prototype
+
+if TYPE_CHECKING:
+    from typing import Any
+
+    import numpy.typing as npt
+
+    from zarr.core.array import Array, AsyncArray
+    from zarr.core.metadata import ArrayV2Metadata, ArrayV3Metadata
+
+
+@dataclass
+class WithShape:
+    shape: tuple[int, ...]
+
+
+@dataclass
+class WithChunks(WithShape):
+    chunks: tuple[int, ...]
+
+
+@dataclass
+class WithChunkLen(WithShape):
+    chunklen: int
+
+
+@pytest.mark.parametrize(
+    ("observed", "expected"),
+    [
+        ({}, (None, None)),
+        (WithShape(shape=(1, 2)), ((1, 2), None)),
+        (WithChunks(shape=(1, 2), chunks=(1, 2)), ((1, 2), (1, 2))),
+        (WithChunkLen(shape=(10, 10), chunklen=1), ((10, 10), (1, 10))),
+    ],
+)
+def test_get_shape_chunks(
+    observed: object, expected: tuple[tuple[int, ...] | None, tuple[int, ...] | None]
+) -> None:
+    """
+    Test the _get_shape_chunks function
+    """
+    assert _get_shape_chunks(observed) == expected
+
+
+@pytest.mark.parametrize(
+    ("observed", "expected"),
+    [
+        (np.arange(10, dtype=np.dtype("int64")), {"shape": (10,), "dtype": np.dtype("int64")}),
+        (WithChunks(shape=(1, 2), chunks=(1, 2)), {"chunks": (1, 2), "shape": (1, 2)}),
+        (
+            create_array(
+                {},
+                chunks=(10,),
+                shape=(100,),
+                dtype="f8",
+                compressors=None,
+                filters=None,
+                zarr_format=2,
+            )._async_array,
+            {
+                "chunks": (10,),
+                "shape": (100,),
+                "dtype": np.dtype("f8"),
+                "compressor": None,
+                "filters": None,
+                "order": "C",
+            },
+        ),
+    ],
+)
+def test_like_args(
+    observed: AsyncArray[ArrayV2Metadata] | AsyncArray[ArrayV3Metadata] | Array | npt.NDArray[Any],
+    expected: object,
+) -> None:
+    """
+    Test the like_args function
+    """
+    assert _like_args(observed, {}) == expected
+
+
+async def test_open_no_array() -> None:
+    """
+    Test that zarr.api.asynchronous.open attempts to open a group when is no array found, but shape was specified in kwargs.
+    This behavior makes no sense but we should still test it.
+    """
+    store = {
+        "zarr.json": default_buffer_prototype().buffer.from_bytes(
+            json.dumps({"zarr_format": 3, "node_type": "group"}).encode("utf-8")
+        )
+    }
+    with pytest.raises(
+        TypeError, match=r"open_group\(\) got an unexpected keyword argument 'shape'"
+    ):
+        await open(store=store, shape=(1,))