diff --git a/karma.conf.js b/karma.conf.js
index 74b08ef..c5aba59 100644
--- a/karma.conf.js
+++ b/karma.conf.js
@@ -1,5 +1,6 @@
 process.env.CHROME_BIN = "chromium-browser";
 var allTests = process.env.ALL_TESTS === "1";
+if (process.env.TEST_MODE !== "unit") require("./tests/run-test-nodes.js")();
 
 module.exports = function(config) {
   config.set({
@@ -14,18 +15,19 @@ module.exports = function(config) {
 
 
     // list of files / patterns to load in the browser
-    files: ["test.js"],
+    files: ["tests/index.js"],
 
 
     // preprocess matching files before serving them to the browser
     // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
     preprocessors: {
-      "test.js": ["browserify", "env"],
+      "tests/index.js": ["browserify", "env"],
     },
 
 
     envPreprocessor: [
       "ALL_TESTS",
+      "TEST_MODE",
     ],
 
 
diff --git a/lib/net/base.js b/lib/net/base.js
index 7eb7c8d..5dfff95 100644
--- a/lib/net/base.js
+++ b/lib/net/base.js
@@ -9,7 +9,7 @@
 
 var inherits = require("inherits");
 var EventEmitter = require("events").EventEmitter;
-var PPromise = require("./platform").Promise;
+var PPromise = require("../platform").Promise;
 
 /**
  * Network transport base class.
diff --git a/lib/net/tcp.browser.js b/lib/net/tcp.browser.js
index 3e631c2..fd53046 100644
--- a/lib/net/tcp.browser.js
+++ b/lib/net/tcp.browser.js
@@ -1 +1 @@
-throw new Error("Not implemented");
+throw new Error("TCP transport is not supported by Browser platform");
diff --git a/package.json b/package.json
index 028dc38..99136e4 100644
--- a/package.json
+++ b/package.json
@@ -11,10 +11,13 @@
   },
   "scripts": {
     "install": "node-gyp rebuild || exit 0",
-    "test": "ALL_TESTS=1 mocha && ALL_TESTS=1 xvfb-run -a karma start --browsers Chromium && ALL_TESTS=1 xvfb-run -a karma start --browsers Firefox && jshint .",
-    "m": "mocha",
-    "k": "xvfb-run -a karma start",
+    "test": "ALL_TESTS=1 mocha tests/index.js && ALL_TESTS=1 xvfb-run -a karma start --browsers Chromium && ALL_TESTS=1 xvfb-run -a karma start --browsers Firefox && jshint .",
+    "m": "mocha tests/index.js",
+    "mu": "TEST_MODE=unit mocha tests/index.js",
+    "mf": "TEST_MODE=functional mocha tests/index.js",
     "kc": "xvfb-run -a karma start --browsers Chromium",
+    "kcu": "TEST_MODE=unit xvfb-run -a karma start --browsers Chromium",
+    "kcf": "TEST_MODE=functional xvfb-run -a karma start --browsers Chromium",
     "kf": "xvfb-run -a karma start --browsers Firefox",
     "j": "jshint .",
     "d": "jsdoc -c jsdoc.json",
diff --git a/tests/functional.js b/tests/functional.js
new file mode 100644
index 0000000..562fe54
--- /dev/null
+++ b/tests/functional.js
@@ -0,0 +1,16 @@
+var bitmessage = require("../lib");
+var structs = bitmessage.structs;
+var message = structs.message;
+// var WsTransport = require("../lib/net/ws").Transport;
+
+if (!process.browser) {
+  var TcpTransport = require("../lib/net/tcp").Transport;
+
+  describe("TCP transport", function() {
+    it("should allow to communicate between two nodes");
+  });
+}
+
+describe("WebSocket transport", function() {
+  it("should allow to communicate between two nodes");
+});
diff --git a/tests/index.js b/tests/index.js
new file mode 100644
index 0000000..0709cd4
--- /dev/null
+++ b/tests/index.js
@@ -0,0 +1,17 @@
+var testMode = (global.__env__ || process.env).TEST_MODE;
+
+if (testMode !== "functional") {
+  describe("Unit tests", function() {
+    require("./unit");
+  });
+}
+
+if (testMode !== "unit") {
+  // For Browser tests nodes are runned from karma.conf.js because we
+  // are _already_ in browser context here.
+  if (!process.browser) require("./run-test-nodes.js")();
+
+  describe("Functional tests", function() {
+    require("./functional");
+  });
+}
diff --git a/tests/run-test-nodes.js b/tests/run-test-nodes.js
new file mode 100644
index 0000000..dc5cb31
--- /dev/null
+++ b/tests/run-test-nodes.js
@@ -0,0 +1,7 @@
+// Run test nodes for all known transports so we can test library in
+// functional test suites. Stop nodes when testing is complete.
+
+// Note that this file is executed only on Node.js platform.
+
+module.exports = function() {
+};
diff --git a/test.js b/tests/unit.js
similarity index 99%
rename from test.js
rename to tests/unit.js
index b461327..8cc20bb 100644
--- a/test.js
+++ b/tests/unit.js
@@ -2,8 +2,8 @@ var expect = require("chai").expect;
 var allTests = (global.__env__ || process.env).ALL_TESTS === "1";
 
 var bufferEqual = require("buffer-equal");
-var bitmessage = require("./lib");
-var bmcrypto = require("./lib/crypto");
+var bitmessage = require("../lib");
+var bmcrypto = require("../lib/crypto");
 var structs = bitmessage.structs;
 var message = structs.message;
 var object = structs.object;