update error messages for ExternalAssetDependency/ExternalAssetDepend…

…edBy (#6748)
dagster-io · Feb 23, 2022 · e83b11c · e83b11c
1 parent 0c55d96
commit e83b11c
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Showing 2 changed files with 12 additions and 8 deletions.
diff --git a/python_modules/dagster/dagster/core/host_representation/external_data.py b/python_modules/dagster/dagster/core/host_representation/external_data.py
@@ -504,7 +504,9 @@ class ExternalAssetDependency(
     def __new__(cls, upstream_asset_key: AssetKey, input_name: str = None, output_name: str = None):
         check.invariant(
             (input_name is None) ^ (output_name is None),
-            "Exactly one of `input_name` and `output_name` should be supplied",
+            "When constructing ExternalAssetDependency, exactly one of `input_name` and "
+            f"`output_name` should be supplied. AssetKey `{upstream_asset_key}` is associated with "
+            f"input `{input_name}` and output `{output_name}`.",
         )
         return super(ExternalAssetDependency, cls).__new__(
             cls,
@@ -529,7 +531,9 @@ def __new__(
     ):
         check.invariant(
             (input_name is None) ^ (output_name is None),
-            "Exactly one of `input_name` and `output_name` should be supplied",
+            "When constructing ExternalAssetDependedBy, exactly one of `input_name` and "
+            f"`output_name` should be supplied. AssetKey `{downstream_asset_key}` is associated with "
+            f"input `{input_name}` and output `{output_name}`.",
         )
         return super(ExternalAssetDependedBy, cls).__new__(
             cls,

diff --git a/..._modules/dagster/dagster_tests/core_tests/host_representation_tests/test_external_data.py b/..._modules/dagster/dagster_tests/core_tests/host_representation_tests/test_external_data.py
@@ -530,22 +530,22 @@ def bar():
 
 
 def test_input_name_or_output_name_dep_by():
-    with pytest.raises(CheckError, match="Exactly one"):
+    with pytest.raises(CheckError, match="input `foo` and output `bar`"):
         ExternalAssetDependedBy(
-            downstream_asset_key=AssetKey("bar"), input_name="foo", output_name="foo"
+            downstream_asset_key=AssetKey("bar"), input_name="foo", output_name="bar"
         )
-    with pytest.raises(CheckError, match="Exactly one"):
+    with pytest.raises(CheckError, match="input `None` and output `None`"):
         ExternalAssetDependedBy(
             downstream_asset_key=AssetKey("bar"), input_name=None, output_name=None
         )
 
 
 def test_input_name_or_output_name_dependency():
-    with pytest.raises(CheckError, match="Exactly one"):
+    with pytest.raises(CheckError, match="input `foo` and output `bar`"):
         ExternalAssetDependency(
-            upstream_asset_key=AssetKey("bar"), input_name="foo", output_name="foo"
+            upstream_asset_key=AssetKey("bar"), input_name="foo", output_name="bar"
         )
-    with pytest.raises(CheckError, match="Exactly one"):
+    with pytest.raises(CheckError, match="input `None` and output `None`"):
         ExternalAssetDependency(
             upstream_asset_key=AssetKey("bar"), input_name=None, output_name=None
         )