chore: present tests

Author: zardoy

package.json

@@ -19,21 +19,35 @@
   "author": "Vitaly <vital2580@icloud.com>",
   "license": "MIT",
   "files": [
-      "build"
+    "build"
   ],
   "scripts": {
-    "prepublishOnly": "tsc",
-    "test": "echo they're definitely needed"
+    "prepublishOnly": "yarn test && tsc",
+    "test": "ava --serial"
   },
   "devDependencies": {
+    "@ava/typescript": "^1.1.1",
+    "@types/jsonfile": "^6.0.0",
     "@types/node": "^15.12.2",
     "@zardoy/tsconfig": "^1.0.2",
+    "ava": "^3.15.0",
+    "del": "^6.0.0",
+    "jsonfile": "^6.1.0",
     "ts-node": "^10.0.0",
     "typescript": "^4.3.2"
   },
   "dependencies": {
     "detect-indent": "^6.1.0",
     "load-json-file": "^6.2.0",
+    "nanoid": "^3.1.23",
     "type-fest": "^1.2.0"
+  },
+  "ava": {
+    "extensions": [
+      "ts"
+    ],
+    "require": [
+      "ts-node/register"
+    ]
   }
 }

readme.md

@@ -57,7 +57,7 @@ We're using [detect-indent](https://www.npmjs.com/package/detect-indent) to pres
 ## TODO
 
 - [ ] Fix. Currently, to preserve the tab size, json file readed twice
-- [ ] tests. should be easy but I'm extremely lazy
+- [ ] Fix double tsc compilation (and test actual build/)
 - [ ] transformer for paths (most likely babel plugin): 
 
 ```ts

tests/index.test.ts

@@ -0,0 +1,38 @@
+import test from "ava";
+
+import jsonfile from "jsonfile";
+import path from "path";
+import del from "del";
+import nanoid from "nanoid";
+import { modifyJsonFile } from "../src/index"
+import fs from "fs/promises";
+
+const jsonFilePath = path.join(__dirname, "testing-file.json");
+
+test.beforeEach(async () => {
+    await jsonfile.writeFile(jsonFilePath, {
+        "name": "package",
+        "main": "index.js",
+        "author": "eldar",
+        "dependencies": {
+            "type-fest": "*",
+            "fdir": ">=2"
+        }
+    }, { spaces: 4 });
+})
+
+test.afterEach.always(async () => {
+    await del(jsonFilePath);
+})
+
+test("modifies JSON file", async t => {
+    await modifyJsonFile(jsonFilePath, {
+        name: s => `super ${s}`,
+        main: "build/electron.js",
+        dependencies: {
+            "type-fest": "^1.0.0"
+        }
+    })
+    const modifiedJsonFle = await fs.readFile(jsonFilePath, "utf8");
+    t.snapshot(modifiedJsonFle);
+})

tests/snapshots/index.test.ts.md

@@ -0,0 +1,18 @@
+# Snapshot report for `tests/index.test.ts`
+
+The actual snapshot is saved in `index.test.ts.snap`.
+
+Generated by [AVA](https://avajs.dev).
+
+## modifies JSON file
+
+> Snapshot 1
+
+    `{␊
+        "name": "super package",␊
+        "main": "build/electron.js",␊
+        "author": "eldar",␊
+        "dependencies": {␊
+            "type-fest": "^1.0.0"␊
+        }␊
+    }`