fix: skip tests if no database run (#28102)

Signed-off-by: yihong0618 <zouzou0208@gmail.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: crazywoola <100913391+crazywoola@users.noreply.github.com>

api/tests/unit_tests/core/workflow/graph_engine/test_database_utils.py

@@ -0,0 +1,46 @@
+"""
+Utilities for detecting if database service is available for workflow tests.
+"""
+
+import psycopg2
+import pytest
+
+from configs import dify_config
+
+
+def is_database_available() -> bool:
+    """
+    Check if the database service is available by attempting to connect to it.
+
+    Returns:
+        True if database is available, False otherwise.
+    """
+    try:
+        # Try to establish a database connection using a context manager
+        with psycopg2.connect(
+            host=dify_config.DB_HOST,
+            port=dify_config.DB_PORT,
+            database=dify_config.DB_DATABASE,
+            user=dify_config.DB_USERNAME,
+            password=dify_config.DB_PASSWORD,
+            connect_timeout=2,  # 2 second timeout
+        ) as conn:
+            pass  # Connection established and will be closed automatically
+        return True
+    except (psycopg2.OperationalError, psycopg2.Error):
+        return False
+
+
+def skip_if_database_unavailable():
+    """
+    Pytest skip decorator that skips tests when database service is unavailable.
+
+    Usage:
+        @skip_if_database_unavailable()
+        def test_my_workflow():
+            ...
+    """
+    return pytest.mark.skipif(
+        not is_database_available(),
+        reason="Database service is not available (connection refused or authentication failed)",
+    )

api/tests/unit_tests/core/workflow/graph_engine/test_iteration_flatten_output.py

@@ -6,9 +6,11 @@ This module tests the iteration node's ability to:
 2. Preserve nested array structure when flatten_output=False
 """
 
+from .test_database_utils import skip_if_database_unavailable
 from .test_table_runner import TableTestRunner, WorkflowTestCase
 
 
+@skip_if_database_unavailable()
 def test_iteration_with_flatten_output_enabled():
     """
     Test iteration node with flatten_output=True (default behavior).
@@ -37,6 +39,7 @@ def test_iteration_with_flatten_output_enabled():
     )
 
 
+@skip_if_database_unavailable()
 def test_iteration_with_flatten_output_disabled():
     """
     Test iteration node with flatten_output=False.
@@ -65,6 +68,7 @@ def test_iteration_with_flatten_output_disabled():
     )
 
 
+@skip_if_database_unavailable()
 def test_iteration_flatten_output_comparison():
     """
     Run both flatten_output configurations in parallel to verify the difference.