reorganize upload code in prep for merge logic, add more tests

src/shared/upload-artifact.ts

@@ -0,0 +1,28 @@
+import * as core from '@actions/core'
+import * as github from '@actions/github'
+import artifact, {UploadArtifactOptions} from '@actions/artifact'
+
+export async function uploadArtifact(
+  artifactName: string,
+  filesToUpload: string[],
+  rootDirectory: string,
+  options: UploadArtifactOptions
+) {
+  const uploadResponse = await artifact.uploadArtifact(
+    artifactName,
+    filesToUpload,
+    rootDirectory,
+    options
+  )
+
+  core.info(
+    `Artifact ${artifactName} has been successfully uploaded! Final size is ${uploadResponse.size} bytes. Artifact ID is ${uploadResponse.id}`
+  )
+  core.setOutput('artifact-id', uploadResponse.id)
+
+  const repository = github.context.repo
+  const artifactURL = `${github.context.serverUrl}/${repository.owner}/${repository.repo}/actions/runs/${github.context.runId}/artifacts/${uploadResponse.id}`
+
+  core.info(`Artifact download URL: ${artifactURL}`)
+  core.setOutput('artifact-url', artifactURL)
+}