Add basic tests for type pretty printing

Author: Premwoik

test/gradient/elixir_type_test.exs

@@ -0,0 +1,48 @@
+defmodule Gradient.ElixirTypeTest do
+  use ExUnit.Case
+  doctest Gradient.ElixirType
+
+  alias Gradient.ElixirType
+
+  test "pp integer()" do
+    type = {:integer, 0, 12}
+    expected = "12"
+    actual = ElixirType.pretty_print(type)
+    assert expected == actual
+  end
+
+  test "pp atom()" do
+    type = {:atom, 0, :ok}
+    expected = ":ok"
+    actual = ElixirType.pretty_print(type)
+    assert expected == actual
+  end
+
+  test "pp nil()" do
+    type = {:atom, 0, nil}
+    expected = "nil"
+    actual = ElixirType.pretty_print(type)
+    assert expected == actual
+  end
+
+  test "pp false boolean()" do
+    type = {:atom, 0, false}
+    expected = "false"
+    actual = ElixirType.pretty_print(type)
+    assert expected == actual
+  end
+
+  test "pp true boolean()" do
+    type = {:atom, 0, true}
+    expected = "true"
+    actual = ElixirType.pretty_print(type)
+    assert expected == actual
+  end
+
+  test "pp binary()" do
+    type = {:type, 0, :binary, []}
+    expected = "binary()"
+    actual = ElixirType.pretty_print(type)
+    assert expected == actual
+  end
+end