Reproduce stale circuit JSON after a failed rebuild

tests/cli/build/build-failed-rebuild-stale-output.test.ts

@@ -0,0 +1,37 @@
+import { expect, test } from "bun:test"
+import { readFile, writeFile } from "node:fs/promises"
+import path from "node:path"
+import { getCliTestFixture } from "../../fixtures/get-cli-test-fixture"
+
+const validCircuitCode = `
+export default () => (
+  <board width="10mm" height="10mm">
+    <resistor resistance="1k" footprint="0402" name="R1" />
+  </board>
+)
+`
+
+const failingCircuitCode = `
+export default () => {
+  throw new Error("intentional failed rebuild")
+}
+`
+
+test("failed rebuild leaves the previous circuit JSON in dist", async () => {
+  const { tmpDir, runCommand } = await getCliTestFixture()
+  const circuitPath = path.join(tmpDir, "index.tsx")
+  const outputPath = path.join(tmpDir, "dist", "index", "circuit.json")
+  await writeFile(path.join(tmpDir, "package.json"), "{}")
+  await writeFile(circuitPath, validCircuitCode)
+
+  const firstBuild = await runCommand("tsci build index.tsx")
+  expect(firstBuild.exitCode).toBe(0)
+  const previousCircuitJson = await readFile(outputPath, "utf8")
+
+  await writeFile(circuitPath, failingCircuitCode)
+  const failedRebuild = await runCommand("tsci build index.tsx")
+
+  expect(failedRebuild.exitCode).toBe(1)
+  expect(failedRebuild.stderr).toContain("intentional failed rebuild")
+  expect(await readFile(outputPath, "utf8")).toBe(previousCircuitJson)
+})