diff --git a/debian/clean b/debian/clean
new file mode 100644
index 0000000..c3af857
--- /dev/null
+++ b/debian/clean
@@ -0,0 +1 @@
+lib/
diff --git a/debian/control b/debian/control
index 1e805ec..460603f 100644
--- a/debian/control
+++ b/debian/control
@@ -5,8 +5,12 @@
 Uploaders: Thorsten Alteholz <debian@alteholz.de>
 Build-Depends: debhelper-compat (= 13)
  , dh-sequence-nodejs
+ , mocha <!nocheck>
  , node-assert <!nocheck>
  , node-boolbase <!nocheck>
+ , node-expect.js <!nocheck>
+ , node-typescript
+ , node-typescript-types
 Standards-Version: 4.5.1
 Vcs-Browser: https://salsa.debian.org/js-team/node-nth-check
 Vcs-Git: https://salsa.debian.org/js-team/node-nth-check.git
diff --git a/debian/tests/pkg-js/files b/debian/tests/pkg-js/files
new file mode 100644
index 0000000..1cbb2d9
--- /dev/null
+++ b/debian/tests/pkg-js/files
@@ -0,0 +1 @@
+debian/tests/test
diff --git a/debian/tests/pkg-js/test b/debian/tests/pkg-js/test
index 92e4509..c05037f 100644
--- a/debian/tests/pkg-js/test
+++ b/debian/tests/pkg-js/test
@@ -1 +1 @@
-node test.js
+mocha debian/tests/test/*.js
diff --git a/debian/tests/test/__fixtures__/rules.js b/debian/tests/test/__fixtures__/rules.js
new file mode 100644
index 0000000..c55b3f8
--- /dev/null
+++ b/debian/tests/test/__fixtures__/rules.js
@@ -0,0 +1,51 @@
+const valid = [
+    ["1", [0, 1]],
+    ["2", [0, 2]],
+    ["3", [0, 3]],
+    ["5", [0, 5]],
+    [" 1 ", [0, 1]],
+    [" 5 ", [0, 5]],
+    ["+2n + 1", [2, 1]],
+    ["-1", [0, -1]],
+    ["-1n + 3", [-1, 3]],
+    ["-1n+3", [-1, 3]],
+    ["-n+2", [-1, 2]],
+    ["-n+3", [-1, 3]],
+    ["0n+3", [0, 3]],
+    ["1n", [1, 0]],
+    ["1n+0", [1, 0]],
+    ["2n", [2, 0]],
+    ["2n + 1", [2, 1]],
+    ["2n+1", [2, 1]],
+    ["3n", [3, 0]],
+    ["3n+0", [3, 0]],
+    ["3n+1", [3, 1]],
+    ["3n+2", [3, 2]],
+    ["3n+3", [3, 3]],
+    ["3n-1", [3, -1]],
+    ["3n-2", [3, -2]],
+    ["3n-3", [3, -3]],
+    ["even", [2, 0]],
+    ["n", [1, 0]],
+    ["n+2", [1, 2]],
+    ["odd", [2, 1]],
+
+    // Surprisingly, neither sizzle, qwery or nwmatcher cover these cases
+    ["-4n+13", [-4, 13]],
+    ["-2n + 12", [-2, 12]],
+];
+
+const invalid = [
+    "-",
+    "- 1n",
+    "-1 n",
+    "2+0",
+    "2n+-0",
+    "an+b",
+    "asdf",
+    "b",
+    "expr",
+    "odd|even|x",
+];
+
+module.exports = {valid, invalid};
diff --git a/debian/tests/test/compile.spec.js b/debian/tests/test/compile.spec.js
new file mode 100644
index 0000000..deac254
--- /dev/null
+++ b/debian/tests/test/compile.spec.js
@@ -0,0 +1,41 @@
+const expect = require('expect.js');
+const nthCheck = require('../../../lib');
+const compile = nthCheck.compile;
+const { valid } = require("./__fixtures__/rules");
+
+const valArray = new Array(...Array(2e3)).map((_, i) => i);
+
+/**
+ * Iterate through all possible values. This is adapted from qwery,
+ * and uses a more intuitive way to process all elements.
+ */
+function slowNth([a, b]) {
+    if (a === 0 && b > 0) return [b - 1];
+
+    return valArray.filter((val) => {
+        for (let i = b; a > 0 ? i <= valArray.length : i >= 1; i += a) {
+            if (val === valArray[i - 1]) return true;
+        }
+        return false;
+    });
+}
+
+describe("parse", () => {
+    it("compile & run all valid", () => {
+        for (const [_, parsed] of valid) {
+            const filtered = valArray.filter(compile(parsed));
+            const iterated = slowNth(parsed);
+
+            expect(filtered).to.eql(iterated);
+        }
+    });
+
+    it("parse, compile & run all valid", () => {
+        for (const [rule, parsed] of valid) {
+            const filtered = valArray.filter(nthCheck.default(rule));
+            const iterated = slowNth(parsed);
+
+            expect([filtered, rule]).to.eql([iterated, rule]);
+        }
+    });
+});
diff --git a/debian/tests/test/parse.spec.js b/debian/tests/test/parse.spec.js
new file mode 100644
index 0000000..73f51fe
--- /dev/null
+++ b/debian/tests/test/parse.spec.js
@@ -0,0 +1,17 @@
+const expect = require('expect.js');
+const { parse } = require("../../../lib/parse");
+const { valid, invalid } = require("./__fixtures__/rules");
+
+describe("parse", () => {
+    it("parse invalid", () => {
+        for (const formula of invalid) {
+            expect(() => parse(formula)).to.throwError(Error);
+        }
+    });
+
+    it("parse valid", () => {
+        for (const [formula, result] of valid) {
+            expect(parse(formula)).to.eql(result);
+        }
+    });
+});