Test runtime header materialization

tests/runtime-header-utils.test.ts

@@ -0,0 +1,36 @@
+import { afterEach, describe, expect, it } from 'vitest';
+import { materializeHeaders } from '../src/runtime-header-utils.js';
+
+describe('materializeHeaders', () => {
+  const envKey = 'HEADER_TOKEN';
+  let previousValue: string | undefined;
+
+  afterEach(() => {
+    if (previousValue === undefined) {
+      delete process.env[envKey];
+    } else {
+      process.env[envKey] = previousValue;
+    }
+    previousValue = undefined;
+  });
+
+  it('resolves environment placeholders in headers', () => {
+    previousValue = process.env[envKey];
+    process.env[envKey] = 'test-secret';
+    const headers = materializeHeaders({ Authorization: `Bearer \${HEADER_TOKEN}` }, 'inline');
+    expect(headers).toEqual({ Authorization: 'Bearer test-secret' });
+  });
+
+  it('propagates a helpful error when placeholder resolution fails', () => {
+    previousValue = process.env[envKey];
+    delete process.env[envKey];
+    expect(() => materializeHeaders({ Authorization: `Bearer \${HEADER_TOKEN}` }, 'broken')).toThrow(
+      /Failed to resolve header 'Authorization'/
+    );
+  });
+
+  it('returns undefined when no headers are provided', () => {
+    const headers = materializeHeaders(undefined, 'noop');
+    expect(headers).toBeUndefined();
+  });
+});