add test binary

databuild/test/BUILD.bazel

@@ -0,0 +1,7 @@
+load("@rules_rust//rust:defs.bzl", "rust_binary")
+
+rust_binary(
+    name = "test_job_helper",
+    srcs = ["test_job_helper.rs"],
+    visibility = ["//visibility:public"],
+)

databuild/test/test_job_helper.rs

@@ -0,0 +1,40 @@
+// Simple test helper binary for testing DataBuild job runs
+// Configurable via environment variables:
+// - DATABUILD_TEST_OUTPUT_FILE: Path to write a marker file
+// - DATABUILD_TEST_EXIT_CODE: Exit code to return (default: 0)
+// - DATABUILD_TEST_STDOUT: Message to write to stdout (default: "test executed")
+// - DATABUILD_TEST_SLEEP_MS: Milliseconds to sleep before exiting (default: 0)
+
+use std::env;
+use std::fs;
+use std::thread;
+use std::time::Duration;
+
+fn main() {
+    // Optional: sleep for testing long-running jobs
+    if let Ok(sleep_ms) = env::var("DATABUILD_TEST_SLEEP_MS") {
+        if let Ok(ms) = sleep_ms.parse::<u64>() {
+            thread::sleep(Duration::from_millis(ms));
+        }
+    }
+
+    // Write to stdout (for capturing output)
+    let stdout_msg = env::var("DATABUILD_TEST_STDOUT")
+        .unwrap_or_else(|_| "test executed".to_string());
+    println!("{}", stdout_msg);
+
+    // Optionally write to a file (for verifying execution)
+    if let Ok(output_file) = env::var("DATABUILD_TEST_OUTPUT_FILE") {
+        let content = env::var("DATABUILD_TEST_FILE_CONTENT")
+            .unwrap_or_else(|_| "test executed".to_string());
+        fs::write(output_file, content).expect("Failed to write output file");
+    }
+
+    // Exit with configured exit code
+    let exit_code = env::var("DATABUILD_TEST_EXIT_CODE")
+        .ok()
+        .and_then(|s| s.parse().ok())
+        .unwrap_or(0);
+
+    std::process::exit(exit_code);
+}