Add PhoenixTest.assert_path and refute_path (#60)

What changed?
============

We add two new assertion helpers to assert on the current path:
`assert_path` and `refute_path`. Both helpers have a 2 and 3 arity
versions. The 3-arity version takes a `query_params` key to assert on
the query params.

We do not handle other optional arguments (such as `host` or `scheme`),
though we could see this being extensible in the future with those
options.

lib/phoenix_test.ex

@@ -433,4 +433,55 @@ defmodule PhoenixTest do
   ```
   """
   defdelegate refute_has(session, selector, opts), to: Assertions
+
+  @doc """
+  Assert helper to verify current request path. Takes an optional `query_params`
+  map.
+
+  ## Examples
+
+  ```elixir
+  # assert we're at /users
+  conn
+  |> visit("/users")
+  |> assert_path("/users")
+
+  # assert we're at /users?name=frodo
+  conn
+  |> visit("/users")
+  |> assert_path("/users", query_params: %{name: "frodo"})
+  ```
+  """
+  defdelegate assert_path(session, path), to: Assertions
+
+  @doc """
+  Same as `assert_path/2` but takes an optional `query_params` map.
+  """
+  defdelegate assert_path(session, path, opts), to: Assertions
+
+  @doc """
+  Verifies current request path is NOT the one provided. Takes an optional
+  `query_params` map for more specificity.
+
+  ## Examples
+
+  ```elixir
+  # refute we're at /posts
+  conn
+  |> visit("/users")
+  |> refute_path("/posts")
+
+  # refute we're at /users?name=frodo
+  conn
+  |> visit("/users?name=aragorn")
+  |> refute_path("/users", query_params: %{name: "frodo"})
+  ```
+  """
+  defdelegate refute_path(session, path), to: Assertions
+
+  @doc """
+  Same as `refute_path/2` but takes an optional `query_params` for more specific
+  refutation.
+  """
+  defdelegate refute_path(session, path, opts), to: Assertions
 end

lib/phoenix_test/assertions.ex

@@ -202,6 +202,88 @@ defmodule PhoenixTest.Assertions do
     session
   end
 
+  def assert_path(session, path) do
+    request_path = session.conn.request_path
+
+    if request_path == path do
+      assert true
+    else
+      msg = """
+      Expected path to be #{inspect(path)} but got #{inspect(request_path)}
+      """
+
+      raise AssertionError, msg
+    end
+
+    session
+  end
+
+  def assert_path(session, path, opts) do
+    params = Keyword.get(opts, :query_params)
+
+    session
+    |> assert_path(path)
+    |> assert_query_params(params)
+  end
+
+  defp assert_query_params(session, params) do
+    conn = session.conn
+
+    if conn.query_params == params do
+      assert true
+    else
+      params_string = URI.encode_query(params)
+
+      msg = """
+      Expected query params to be #{inspect(params_string)} but got #{inspect(conn.query_string)}
+      """
+
+      raise AssertionError, msg
+    end
+
+    session
+  end
+
+  def refute_path(session, path) do
+    request_path = session.conn.request_path
+
+    if request_path == path do
+      msg = """
+      Expected path not to be #{inspect(path)}
+      """
+
+      raise AssertionError, msg
+    else
+      refute false
+    end
+
+    session
+  end
+
+  def refute_path(session, path, opts) do
+    params = Keyword.get(opts, :query_params)
+
+    refute_query_params(session, params) || refute_path(session, path)
+  end
+
+  defp refute_query_params(session, params) do
+    conn = session.conn
+
+    if conn.query_params == params do
+      params_string = URI.encode_query(params)
+
+      msg = """
+      Expected query params not to be #{inspect(params_string)}
+      """
+
+      raise AssertionError, msg
+    else
+      refute false
+    end
+
+    session
+  end
+
   defp assert_incorrect_count_error_msg(selector, opts, found) do
     text = Keyword.get(opts, :text, :no_text)
     expected_count = Keyword.get(opts, :count, :any)

test/phoenix_test/assertions_test.exs

@@ -572,4 +572,88 @@ defmodule PhoenixTest.AssertionsTest do
       end
     end
   end
+
+  describe "assert_path" do
+    test "asserts that the given path is the current path", %{conn: conn} do
+      conn
+      |> visit("/page/index")
+      |> assert_path("/page/index")
+    end
+
+    test "asserts query params are the same", %{conn: conn} do
+      conn
+      |> visit("/page/index?hello=world")
+      |> assert_path("/page/index", query_params: %{"hello" => "world"})
+    end
+
+    test "raises helpful error if path doesn't match", %{conn: conn} do
+      msg =
+        """
+        Expected path to be "/page/not-index" but got "/page/index"
+        """
+        |> ignore_whitespace()
+
+      assert_raise AssertionError, msg, fn ->
+        conn
+        |> visit("/page/index")
+        |> assert_path("/page/not-index")
+      end
+    end
+
+    test "raises helpful error if query params don't match", %{conn: conn} do
+      msg =
+        """
+        Expected query params to be "goodbye=world&hi=bye" but got "hello=world&hi=bye"
+        """
+        |> ignore_whitespace()
+
+      assert_raise AssertionError, msg, fn ->
+        conn
+        |> visit("/page/index?hello=world&hi=bye")
+        |> assert_path("/page/index", query_params: %{"goodbye" => "world", "hi" => "bye"})
+      end
+    end
+  end
+
+  describe "refute_path" do
+    test "refute that the given path is the current path", %{conn: conn} do
+      conn
+      |> visit("/page/index")
+      |> refute_path("/page/page_2")
+    end
+
+    test "refutes query params are the same", %{conn: conn} do
+      conn
+      |> visit("/page/index?hello=world")
+      |> refute_path("/page/index", query_params: %{"hello" => "not-world"})
+    end
+
+    test "raises helpful error if path matches", %{conn: conn} do
+      msg =
+        """
+        Expected path not to be "/page/index"
+        """
+        |> ignore_whitespace()
+
+      assert_raise AssertionError, msg, fn ->
+        conn
+        |> visit("/page/index")
+        |> refute_path("/page/index")
+      end
+    end
+
+    test "raises helpful error if query params don't match", %{conn: conn} do
+      msg =
+        """
+        Expected query params not to be "hello=world&hi=bye"
+        """
+        |> ignore_whitespace()
+
+      assert_raise AssertionError, msg, fn ->
+        conn
+        |> visit("/page/index?hello=world&hi=bye")
+        |> refute_path("/page/index", query_params: %{"hello" => "world", "hi" => "bye"})
+      end
+    end
+  end
 end