Improves test coverage.

tests/libp2p-tcp-test.js

@@ -15,6 +15,19 @@ describe('libp2p-tcp', function () {
     done()
   })
 
+  it('create without new', (done) => {
+    tcp = TCPlibp2p()
+    expect(tcp).to.exist
+    done()
+  })
+
+  it('close /wo listeners', (done) => {
+    tcp = new TCPlibp2p()
+    expect(tcp).to.exist
+    expect(function () { tcp.close() }).to.throw(Error)
+    done()
+  })
+
   it('listen', (done) => {
     const mh = multiaddr('/ip4/127.0.0.1/tcp/9090')
     tcp.createListener(mh, (socket) => {
@@ -88,5 +101,14 @@ describe('libp2p-tcp', function () {
     done()
   })
 
+  it('filter a valid addr for this transport', (done) => {
+    const mh1 = multiaddr('/ip4/127.0.0.1/tcp/9090')
+
+    const valid = tcp.filter(mh1)
+    expect(valid.length).to.equal(1)
+    expect(valid[0]).to.deep.equal(mh1)
+    done()
+  })
+
   it.skip('listen on IPv6', (done) => {})
 })