1 files changed, 85 insertions, 0 deletions
diff --git a/tests/type-consistency/harness.ts b/tests/type-consistency/harness.ts
new file mode 100644
index 0000000..a08e397
--- /dev/null
+++ b/tests/type-consistency/harness.ts
@@ -0,0 +1,85 @@
+import fs from "fs/promises";
+import path from "path";
+
+const convertName = (name: string) => name.replace(" ", "-").toLowerCase();
+
+export const createTestHarness = ({
+  harnessName,
+  generatedPath,
+}: {
+  harnessName: string;
+  generatedPath: string;
+}) => {
+  const tests: string[] = [];
+
+  return {
+    async writeTests() {
+      const file = `import { evaluateProgram, createFn } from "../../../src";
+import { describe, expect, expectTypeOf, test } from "vitest";
+
+describe(\`${harnessName}\`, () => {
+      ${tests.join("\n")}
+    });`;
+
+      await fs.mkdir(generatedPath, { recursive: true });
+
+      await fs.writeFile(
+        path.join(generatedPath, `${convertName(harnessName)}.test.ts`),
+        file,
+        "utf-8"
+      );
+
+      console.log(`Wrote ${tests.length} test(s) for "${harnessName}"!`);
+    },
+
+    createProgramTest({
+      name,
+      program,
+      expected,
+    }: {
+      name: string;
+      program: string;
+      expected: any;
+    }) {
+      tests.push(`test(\`${name}\`, () => {
+    const PROGRAM = \`${program}\` as const;
+    const expected: ${JSON.stringify(expected)} = ${JSON.stringify(expected)};
+    const result = evaluateProgram(PROGRAM);
+
+    expect(result).toStrictEqual(expected);
+    expectTypeOf<typeof result>().toEqualTypeOf<typeof expected>();
+      });`);
+
+      return this;
+    },
+
+    createFunctionTest({
+      name,
+      program,
+      cases,
+    }: {
+      name: string;
+      program: string;
+      cases: Array<{ input: any; output: any }>;
+    }) {
+      tests.push(`describe(\`${name}\`, () => {
+    const PROGRAM = \`${program}\` as const;
+    ${cases.map(
+      ({ input, output }) => `test(\`${JSON.stringify(
+        input
+      )} -> ${JSON.stringify(output)}\`, () => {
+    const input: ${JSON.stringify(input)} = ${JSON.stringify(input)};
+    const expected: ${JSON.stringify(output)} = ${JSON.stringify(output)};
+    const fn = createFn()(PROGRAM)
+    const result = fn(input)
+
+    expect(result).toStrictEqual(expected);
+    expectTypeOf<typeof result>().toEqualTypeOf<typeof expected>();
+      })
+      `
+    )}});`);
+
+      return this;
+    },
+  };
+};