Add input validations with tests.

src/input-validator.ts

@@ -0,0 +1,32 @@
+import { isNumber } from "util";
+
+export const MIN_API_LEVEL = 21;
+export const VALID_TARGETS: Array<string> = ['default', 'google_apis'];
+export const VALID_ABIS: Array<string> = ['x86', 'x86_64'];
+
+export function checkApiLevel(apiLevel: string): void {
+  if (isNaN(Number(apiLevel)) || !Number.isInteger(Number(apiLevel))) {
+    throw new Error(`Unexpected API level: '${apiLevel}'.`);
+  }
+  if (Number(apiLevel) < MIN_API_LEVEL) {
+    throw new Error(`Minimum API level supported is ${MIN_API_LEVEL}.`);
+  }
+}
+
+export function checkTarget(target: string): void {
+  if (!VALID_TARGETS.includes(target)) {
+    throw new Error(`Value for input.target '${target}' is unknown. Supported options: ${VALID_TARGETS}.`);
+  }
+}
+
+export function checkAbi(abi: string): void {
+  if (!VALID_ABIS.includes(abi)) {
+    throw new Error(`Value for input.abi '${abi}' is unknown. Supported options: ${VALID_ABIS}.`);
+  }
+}
+
+export function checkHeadless(headless: string): void {
+  if (headless !== 'true' && headless !== 'false') {
+    throw new Error(`Input for input.headless should be either 'true' or 'false'.`);
+  }
+}