add test preview

tests/test_preview.py

@@ -0,0 +1,63 @@
+import os
+
+from iact3.cli_modules.preview import Preview
+from iact3.config import IAC_NAME
+from tests.common import BaseTest
+import logging
+import logging.handlers
+
+class TestRun(BaseTest):
+    async def test_preview_with_valid_config(self):
+        config_file = os.path.join(self.DATA_PATH, 'test_config.iact3.yaml')
+
+        memory_handler = logging.handlers.MemoryHandler(capacity=10240)
+        logger = logging.getLogger()
+        logger.addHandler(memory_handler)
+
+        await Preview.create(config_file=config_file)
+
+        logs = memory_handler.buffer
+
+        self.assertIn("test_name: default", logs[6].getMessage())
+        self.assertIn("VPC::EIPAssociation", logs[10].getMessage())
+        self.assertIn("\"AllocationId\": \"EIP\",", logs[11].getMessage())
+
+    async def test_preview_with_invalid_config(self):
+        config_file = os.path.join(self.DATA_PATH, 'failed_cost_config.iact3.yaml')
+
+        memory_handler = logging.handlers.MemoryHandler(capacity=10240)
+        logger = logging.getLogger()
+        logger.addHandler(memory_handler)
+
+        await Preview.create(config_file=config_file)
+
+        logs = memory_handler.buffer
+
+        self.assertIn("test_name: default", logs[6].getMessage())
+        self.assertIn("region: cn-hangzhou", logs[7].getMessage())
+        self.assertIn("StackValidationFailed", logs[8].getMessage())
+        self.assertIn("code:", logs[9].getMessage())
+
+    async def test_preview_with_only_template(self):
+        template = os.path.join(self.DATA_PATH, 'simple_template.yml')
+
+        with self.assertRaises(FileNotFoundError) as cm:
+            await Preview.create(template=template)
+        ex = cm.exception
+        self.assertEqual(ex.errno, 2)
+        self.assertEqual(True, ex.filename.endswith(f'.{IAC_NAME}.yml'))
+
+    async def test_preview_with_multi_region(self):
+        config_file = os.path.join(self.DATA_PATH, 'test_config.iact3.yaml')
+
+        memory_handler = logging.handlers.MemoryHandler(capacity=10240)
+        logger = logging.getLogger()
+        logger.addHandler(memory_handler)
+
+        await Preview.create(config_file=config_file,regions="cn-hangzhou,cn-beijing")
+
+        logs = memory_handler.buffer
+
+        self.assertIn("test_name: default", logs[11].getMessage())
+        self.assertIn("test_name: default", logs[100].getMessage())
+