test(shell): emit JSON via sys.executable for cross-platform output_format tests

Address review (#2963): replace non-portable echo '{...}' (Windows cmd.exe keeps the single quotes, breaking JSON) with the established '"{py}" "{script}"' pattern using sys.executable + a temp script, so the output_format tests pass on the Windows CI matrix. Also make the validate test's run inert (exit 0).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: doquanghuy

tests/test_workflows.py

@@ -945,11 +945,18 @@ def test_output_format_json_exposes_data(self, tmp_path):
         from specify_cli.workflows.steps.shell import ShellStep
         from specify_cli.workflows.base import StepContext, StepStatus
 
+        import sys
+
+        py = sys.executable
+        script = tmp_path / "emit.py"
+        script.write_text(
+            'import json; print(json.dumps({"items": [1, 2]}))\n', encoding="utf-8"
+        )
         step = ShellStep()
         ctx = StepContext(project_root=str(tmp_path))
         config = {
             "id": "emit",
-            "run": "echo '{\"items\": [1, 2]}'",
+            "run": f'"{py}" "{script}"',
             "output_format": "json",
         }
         result = step.execute(config, ctx)
@@ -961,11 +968,16 @@ def test_output_format_json_invalid_stdout_fails(self, tmp_path):
         from specify_cli.workflows.steps.shell import ShellStep
         from specify_cli.workflows.base import StepContext, StepStatus
 
+        import sys
+
+        py = sys.executable
+        script = tmp_path / "emit.py"
+        script.write_text("print('not-json')\n", encoding="utf-8")
         step = ShellStep()
         ctx = StepContext(project_root=str(tmp_path))
         config = {
             "id": "emit",
-            "run": "echo not-json",
+            "run": f'"{py}" "{script}"',
             "output_format": "json",
         }
         result = step.execute(config, ctx)
@@ -976,9 +988,16 @@ def test_no_output_format_keeps_raw_output_only(self, tmp_path):
         from specify_cli.workflows.steps.shell import ShellStep
         from specify_cli.workflows.base import StepContext, StepStatus
 
+        import sys
+
+        py = sys.executable
+        script = tmp_path / "emit.py"
+        script.write_text(
+            'import json; print(json.dumps({"items": []}))\n', encoding="utf-8"
+        )
         step = ShellStep()
         ctx = StepContext(project_root=str(tmp_path))
-        config = {"id": "emit", "run": "echo '{\"items\": []}'"}
+        config = {"id": "emit", "run": f'"{py}" "{script}"'}
         result = step.execute(config, ctx)
         assert result.status == StepStatus.COMPLETED
         assert "data" not in result.output
@@ -987,7 +1006,7 @@ def test_validate_rejects_unknown_output_format(self):
         from specify_cli.workflows.steps.shell import ShellStep
 
         step = ShellStep()
-        errors = step.validate({"id": "emit", "run": "true", "output_format": "yaml"})
+        errors = step.validate({"id": "emit", "run": "exit 0", "output_format": "yaml"})
         assert any("'output_format' must be 'json'" in e for e in errors)
 
 class _StubStdin: