add test cases

Author: Mathiyarasy

src/spec-node/dockerfilePreprocessor.ts

@@ -49,6 +49,23 @@ export async function preprocessDockerExtensionFile(
 	const inputPath = dockerfilePath;
 	const outputPath = cliOutputPath;
 	const generatedOutputPath = generatedDockerfile ? path.resolve(workdirPath, generatedDockerfile) : outputPath;
+	const staleOutputPaths = generatedOutputPath === outputPath ? [outputPath] : [outputPath, generatedOutputPath];
+	for (const stalePath of staleOutputPaths) {
+		if (!await cliHost.isFile(stalePath)) {
+			continue;
+		}
+		const cleanupCommand = cliHost.platform === 'win32'
+			? { cmd: 'cmd', args: ['/d', '/s', '/c', `del /f /q "${stalePath}"`] }
+			: { cmd: 'rm', args: ['-f', stalePath] };
+		await runCommandNoPty({
+			exec: cliHost.exec,
+			cmd: cleanupCommand.cmd,
+			args: cleanupCommand.args,
+			cwd: workdirPath,
+			env: cliHost.env,
+			output: infoOutput,
+		});
+	}
 
 	// Strict contract: the CLI owns the final output path. Direct-transform
 	// tools can write to the CLI-provided output argument; workspace generators

src/test/configs/dockercomposefile-cpp-preprocessor/.devcontainer/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "Docker Compose Cpp Preprocessor",
+	"dockerComposeFile": "docker-compose.yml",
+	"service": "app",
+	"workspaceFolder": "/workspace",
+	"dockerfilePreprocessor": {
+		"tool": "cpp",
+		"outputMode": "single-file",
+		"args": [
+			"-P"
+		]
+	},
+	"features": {
+		"ghcr.io/devcontainers/features/github-cli:1": {
+			"version": "latest"
+		}
+	}
+}

src/test/configs/dockercomposefile-cpp-preprocessor/.devcontainer/docker-compose.yml

@@ -0,0 +1,10 @@
+version: '3.8'
+
+services:
+  app:
+    build:
+      context: ..
+      dockerfile: Dockerfile.in
+    command: sleep infinity
+    volumes:
+      - ..:/workspace:cached

src/test/configs/dockercomposefile-cpp-preprocessor/Dockerfile.in

@@ -0,0 +1,16 @@
+#define BASE_IMAGE ubuntu:20.04
+#define INSTALL_NODE
+#define INSTALL_PYTHON
+
+FROM BASE_IMAGE
+
+#ifdef INSTALL_NODE
+RUN apt-get update && apt-get install -y nodejs
+#endif
+
+#ifdef INSTALL_PYTHON
+RUN apt-get update && apt-get install -y python3
+#endif
+
+#include "common.Dockerfile"
+#include "tools.Dockerfile"

src/test/configs/dockercomposefile-cpp-preprocessor/common.Dockerfile

@@ -0,0 +1 @@
+RUN apt-get update && apt-get install -y curl wget

src/test/configs/dockercomposefile-cpp-preprocessor/test.sh

@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+echo hello

src/test/configs/dockercomposefile-cpp-preprocessor/tools.Dockerfile

@@ -0,0 +1,2 @@
+RUN apt-get update && apt-get install -y vim
+COPY ./test.sh /usr/local/bin/test.sh

src/test/configs/dockerfile-autoconf-preprocessor/.devcontainer.json

@@ -3,11 +3,12 @@
 		"dockerfile": "Dockerfile.in"
 	},
 	"dockerfilePreprocessor": {
-		"commands": [
-			"autoconf",
-			"./configure"
+		"tool": "sh",
+		"args": [
+			"-c",
+			"autoconf && ./configure"
 		],
-		"output": "Dockerfile"
+		"generatedDockerfile": "Dockerfile"
 	},
 	"features": {
 		"ghcr.io/devcontainers/features/github-cli:1": {