Fixes some Crystal compatibility issues

.gitignore

@@ -1,3 +1,3 @@
-.crystal
-.shards
-libs
+/.crystal
+/.shards
+/lib

README.md

@@ -2,6 +2,16 @@
 
 Selenium Webdriver bindings for the Crystal programming language.
 
+WARNING: this implements the now obsolete
+[JsonWireProtocol](https://github.com/SeleniumHQ/selenium/wiki/JsonWireProtocol)
+the [W3C Webdriver spec](https://w3c.github.io/webdriver/webdriver-spec.html).
+Your selenium and browser mileages may not be supported until the new protocol
+is implemented.
+
+Latest known working combination is Selenium 2.48.2 and Firefox 34. A
+combination known to NOT WORK is Selenium 3.5.3, Firefox 55 and the now required
+Geckodriver 0.18.0.
+
 
 ## Usage
 

shard.lock

@@ -2,5 +2,5 @@ version: 1.0
 shards:
   minitest:
     github: ysbaddaden/minitest.cr
-    version: 0.3.4
+    version: 0.3.5
 

src/webdriver.cr

@@ -20,7 +20,7 @@ module Selenium
 
       case response.status_code
       when 200
-        JSON.parse(response.body).raw as Hash
+        JSON.parse(response.body).raw.as(Hash)
       else
         failure(response)
       end

src/webdriver/alert.cr

@@ -1,6 +1,6 @@
 module Selenium
   class Alert
-    private getter :session
+    private getter session : Session
 
     def initialize(@session)
     end

src/webdriver/session.cr

@@ -40,11 +40,11 @@ module Selenium
       delete
     end
 
-    def timeouts=(script : Int = nil, implicit : Int = nil, page_load : Int = nil)
-      body = {} of Symbol => String | Nil
-      body[:script] = script if script
-      body[:implicit] = implicit if implicit
-      body[:page_load] = page_load if page_load
+    def timeouts(script : Int? = nil, implicit : Int? = nil, page_load : Int? = nil)
+      body = {} of Symbol => Int32?
+      body[:script] = script.to_i if script
+      body[:implicit] = implicit.to_i if implicit
+      body[:page_load] = page_load.to_i if page_load
       post("/timeouts", body)
     end
 
@@ -97,7 +97,7 @@ module Selenium
     #  post("/screenshot")
     #end
 
-    def find_element(by, selector, parent : WebElement = nil)
+    def find_element(by, selector, parent : WebElement? = nil)
       url = parent ? "/element/#{ parent.id }/element" : "/element"
       value = post(url, {
         using: WebElement.locator_for(by),
@@ -106,7 +106,7 @@ module Selenium
       WebElement.new(self, value.as(Hash))
     end
 
-    def find_elements(by, selector, parent : WebElement = nil)
+    def find_elements(by, selector, parent : WebElement? = nil)
       url = parent ? "/element/#{ parent.id }/elements" : "/elements"
       value = post(url, {
         using: WebElement.locator_for(by),

src/webdriver/web_element.cr

@@ -59,7 +59,7 @@ module Selenium
     #  Numpad 9  U+E023
     #}
 
-    getter id
+    getter id : String
     private getter session : Session
 
     def initialize(@session, item)

test/session_test.cr

@@ -5,24 +5,31 @@ class SessionTest < Minitest::Test
     session.url = "https://crystal-lang.org"
     assert_equal "https://crystal-lang.org/", session.url
 
-    nav = session.find_element(:css, "nav .menu")
+    nav = session.find_element(:css, "nav[role=navigation]")
 
-    links = nav.find_elements(:tag_name, "a")
-    assert_equal ["GITHUB", "DOCS", "API"], links.map(&.text)
+    links = nav.find_elements(:tag_name, "a").map(&.text)
+    assert_includes links, "Blog"
+    assert_includes links, "GitHub"
+    assert_includes links, "Docs"
+    assert_includes links, "API"
 
     session.execute <<-JAVASCRIPT
     Array.from(document.querySelectorAll("nav .menu a"))
       .forEach(function (a) { a.removeAttribute("target"); })
     JAVASCRIPT
 
-    nav.find_element(:css, "a[title='API']").click
-    assert_match "https://crystal-lang.org/api/", session.url
+    assert_raises(Selenium::NoSuchElement) do
+      nav.find_element(:css, "a[href='/some/unknown/link']")
+    end
+
+    nav.find_element(:css, "a[href='/blog/']").click
+    assert_match "https://crystal-lang.org/blog/", session.url
 
     session.back
     assert_equal "https://crystal-lang.org/", session.url
 
     session.forward
-    assert_match "https://crystal-lang.org/api/", session.url
+    assert_match "https://crystal-lang.org/blog/", session.url
   end
 
   def test_input