fix: Adds get_jobs_replaced() to decoder

Author: Alan Christie

decoder/decoder.py

@@ -54,6 +54,11 @@ class TextEncoding(enum.Enum):
     JINJA2_3_0 = 1  # Encoding that complies with Jinja2 v3.0.x
 
 
+def get_job_key(collection: str, job: str) -> str:
+    """Returns the job Key, a string formed from "<collection>|<job>."""
+    return f"{collection}|{job}"
+
+
 def validate_manifest_schema(manifest: Dict[str, Any]) -> Optional[str]:
     """Checks the Job Definition Manifest (a preloaded job-definition dictionary)
     against the built-in schema. If there's an error the error text is
@@ -298,6 +303,22 @@ def get_environment_assets(job_definition: Dict[str, Any]) -> List[Dict[str, str
     return env_assets
 
 
+def get_jobs_replaced(job_definition: Dict[str, Any]) -> Optional[List[str]]:
+    """Given a Job Definition this function returns the Jobs it replaces.
+    The returned list is a list of jobs identified by collection and
+    job delimited with '|', e.g. string like "test-collection|test-job".
+    """
+    replaces_list: List[Dict[str, str]] = job_definition.get("replaces", [])
+    if not replaces_list:
+        return None
+    replaced: Set[str] = set()
+    for replaces in replaces_list:
+        r_collection: str = replaces["collection"]
+        r_job: str = replaces["job"]
+        replaced.add(get_job_key(r_collection, r_job))
+    return list(replaced)
+
+
 def decode(
     template_text: str,
     variable_map: Optional[Dict[str, str]],

tests/test_get_jobs_replaced.py

@@ -0,0 +1,40 @@
+# Tests for the decoder's get_jobs_replaced() function.
+from typing import Dict
+
+import pytest
+
+pytestmark = pytest.mark.unit
+
+from decoder import decoder
+
+
+def test_get_jobs_replaced_when_none():
+    # Arrange
+    job_definition: Dict = {}
+
+    # Act
+    replaced = decoder.get_jobs_replaced(job_definition)
+
+    # Assert
+    assert replaced is None
+
+
+def test_get_jobs_replaced():
+    # Arrange
+    collection: str = "collection-x"
+    job: str = "job-x"
+    job_definition: Dict = {
+        "replaces": [
+            {"collection": "c-1", "job": "j-1"},
+            {"collection": "c-1", "job": "j-2"},
+        ]
+    }
+
+    # Act
+    replaced = decoder.get_jobs_replaced(job_definition)
+
+    # Assert
+    assert replaced
+    assert len(replaced) == 2
+    assert "c-1|j-1" in replaced
+    assert "c-1|j-2" in replaced