diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
new file mode 100644
index 0000000..ca0246c
--- /dev/null
+++ b/.github/workflows/main.yml
@@ -0,0 +1,45 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+env:
+  JAVA_VERSION: 21
+
+jobs:
+  test:
+    strategy:
+      fail-fast: false
+      matrix:
+        node-version: ['22.x']
+        os: [ubuntu-latest, windows-2022, macos-latest]
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Setup Java
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: ${{ env.JAVA_VERSION }}
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          registry-url: 'https://registry.npmjs.org/'
+
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Build the project
+        run: npm run build
+
+      - name: Run tests
+        run: npm run test
diff --git a/jest.config.js b/jest.config.js
index e142053..8ccda6d 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -1,14 +1,6 @@
-import { weaverConfig } from "@specs-feup/clava/code/WeaverConfiguration.js";
-
 const config = {
   preset: "ts-jest/presets/default-esm",
-  testEnvironment: "@specs-feup/lara/jest/jestEnvironment.js",
-  testEnvironmentOptions: {
-    weaverConfig,
-  },
-  globalSetup: "@specs-feup/lara/jest/jestGlobalSetup.js",
-  globalTeardown: "@specs-feup/lara/jest/jestGlobalTeardown.js",
-  setupFiles: ["@specs-feup/lara/jest/setupFiles/sharedJavaModule.js"],
+  testEnvironment: "node",
   //notify: true,
   //notifyMode: "always",
   //verbose: true,
diff --git a/package.json b/package.json
index 696d8c8..d91b6d8 100644
--- a/package.json
+++ b/package.json
@@ -29,7 +29,7 @@
     "test:watch": "npm run test -- --watch"
   },
   "dependencies": {
-    "@specs-feup/lara": "^3.0.4",
+    "@specs-feup/lara": "^3.5.2",
     "express": "^4.21.2",
     "ws": "^8.18.0"
   },
diff --git a/src/AstConverterUtils.test.ts b/src/AstConverterUtils.test.ts
new file mode 100644
index 0000000..0e5e8dc
--- /dev/null
+++ b/src/AstConverterUtils.test.ts
@@ -0,0 +1,60 @@
+import {
+  addIdentation,
+  escapeHtml,
+  getNodeCodeTags,
+  getSpanTags,
+  getSyntaxHighlightTags,
+  normalizeFilepath,
+} from "./AstConverterUtils.js";
+
+describe("AstConverterUtils", () => {
+  describe("addIdentation", () => {
+    it("indents every line except the first one", () => {
+      expect(addIdentation("first\nsecond\nthird", 2)).toBe(
+        "first\n      second\n      third"
+      );
+    });
+
+    it("leaves single-line code unchanged", () => {
+      expect(addIdentation("const value = 1;", 3)).toBe("const value = 1;");
+    });
+  });
+
+  it("escapes HTML control characters without changing other text", () => {
+    expect(escapeHtml("if (left < right && right > 0)"))
+      .toBe("if (left &lt; right &amp;&amp; right &gt; 0)");
+  });
+
+  it("creates generic span tags with all supplied attributes", () => {
+    expect(getSpanTags('class="node"', 'data-id="42"')).toEqual([
+      '<span class="node" data-id="42">',
+      "</span>",
+    ]);
+  });
+
+  it("creates node-code span tags", () => {
+    expect(getNodeCodeTags("node-7")).toEqual([
+      '<span class="node-code" data-node-id="node-7">',
+      "</span>",
+    ]);
+  });
+
+  it.each(["comment", "keyword", "literal", "string", "type"] as const)(
+    "creates %s syntax-highlighting tags",
+    (type) => {
+      expect(getSyntaxHighlightTags(type)).toEqual([
+        `<span class="${type}">`,
+        "</span>",
+      ]);
+    }
+  );
+
+  it("normalizes Windows separators and preserves POSIX separators", () => {
+    expect(normalizeFilepath("src\\public\\index.html")).toBe(
+      "src/public/index.html"
+    );
+    expect(normalizeFilepath("src/public/index.html")).toBe(
+      "src/public/index.html"
+    );
+  });
+});
diff --git a/src/public/js/ToolJoinPoint.test.ts b/src/public/js/ToolJoinPoint.test.ts
new file mode 100644
index 0000000..51c5851
--- /dev/null
+++ b/src/public/js/ToolJoinPoint.test.ts
@@ -0,0 +1,69 @@
+import ToolJoinPoint from "./ToolJoinPoint.js";
+
+describe("ToolJoinPoint", () => {
+  const jsonTree = {
+    id: "root",
+    type: "program",
+    code: "const answer = 42;",
+    filepath: "src/example.ts",
+    info: { language: "TypeScript" },
+    children: [
+      {
+        id: "child",
+        type: "declaration",
+        code: "const answer = 42;",
+        filepath: "src/example.ts",
+        info: { name: "answer" },
+        children: [],
+      },
+    ],
+  };
+
+  it("builds a nested join-point tree from JSON", () => {
+    const root = ToolJoinPoint.fromJson(jsonTree);
+
+    expect(root.id).toBe("root");
+    expect(root.type).toBe("program");
+    expect(root.code).toBe("const answer = 42;");
+    expect(root.filepath).toBe("src/example.ts");
+    expect(root.info).toEqual({ language: "TypeScript" });
+    expect(root.children).toHaveLength(1);
+    expect(root.children[0]).toBeInstanceOf(ToolJoinPoint);
+    expect(root.children[0].id).toBe("child");
+  });
+
+  it("serializes a nested join-point tree to JSON", () => {
+    expect(ToolJoinPoint.fromJson(jsonTree).toJson()).toEqual(jsonTree);
+  });
+
+  it("clones the complete tree into new join-point instances", () => {
+    const original = ToolJoinPoint.fromJson(jsonTree);
+    const clone = original.clone();
+
+    expect(clone).not.toBe(original);
+    expect(clone.children[0]).not.toBe(original.children[0]);
+    expect(clone.toJson()).toEqual(original.toJson());
+  });
+
+  it("supports join points without code or a filepath", () => {
+    const joinPoint = new ToolJoinPoint(
+      "synthetic",
+      "scope",
+      undefined,
+      undefined,
+      {},
+      []
+    );
+
+    expect(joinPoint.code).toBeUndefined();
+    expect(joinPoint.filepath).toBeUndefined();
+    expect(joinPoint.toJson()).toEqual({
+      id: "synthetic",
+      type: "scope",
+      code: undefined,
+      filepath: undefined,
+      info: {},
+      children: [],
+    });
+  });
+});
diff --git a/src/public/js/utils.test.ts b/src/public/js/utils.test.ts
new file mode 100644
index 0000000..fd24985
--- /dev/null
+++ b/src/public/js/utils.test.ts
@@ -0,0 +1,15 @@
+import { countChar } from "./utils.js";
+
+describe("countChar", () => {
+  it("counts every occurrence of the requested character", () => {
+    expect(countChar("abracadabra", "a")).toBe(5);
+  });
+
+  it("returns zero when the character is absent", () => {
+    expect(countChar("visualization", "x")).toBe(0);
+  });
+
+  it("handles Unicode characters", () => {
+    expect(countChar("a✨b✨c", "✨")).toBe(2);
+  });
+});