Allow java-version: 'dev' if version: 'dev'.

Fixes #30

__tests__/graalvm.test.ts

@@ -1,6 +1,9 @@
 import * as path from 'path'
 import * as graalvm from '../src/graalvm'
 import {expect, test} from '@jest/globals'
+import {getLatestRelease} from '../src/utils'
+import {findGraalVMVersion, findHighestJavaVersion} from '../src/graalvm'
+import {GRAALVM_RELEASES_REPO} from '../src/constants'
 
 process.env['RUNNER_TOOL_CACHE'] = path.join(__dirname, 'TOOL_CACHE')
 process.env['RUNNER_TEMP'] = path.join(__dirname, 'TEMP')
@@ -23,3 +26,27 @@ test('request invalid version/javaVersion', async () => {
     expect(error.message).toContain('Are you sure version')
   }
 })
+
+test('find version/javaVersion', async () => {
+  const latestRelease = await getLatestRelease(GRAALVM_RELEASES_REPO)
+  const latestVersion = findGraalVMVersion(latestRelease)
+  expect(latestVersion).not.toBe('')
+  const latestJavaVersion = findHighestJavaVersion(latestRelease, latestVersion)
+  expect(latestJavaVersion).not.toBe('')
+
+  let error = new Error('unexpected')
+  try {
+    const invalidRelease = {...latestRelease, tag_name: 'invalid'}
+    findGraalVMVersion(invalidRelease)
+  } catch (err) {
+    error = err
+  }
+  expect(error.message).toContain('Could not find latest GraalVM release:')
+
+  try {
+    findHighestJavaVersion(latestRelease, 'invalid')
+  } catch (err) {
+    error = err
+  }
+  expect(error.message).toContain('Could not find highest Java version.')
+})