Handle valid? check for access_scopes

lib/shopify_api/session.rb

@@ -145,7 +145,7 @@ def api_version=(version)
     end
 
     def valid?
-      domain.present? && token.present? && api_version.is_a?(ApiVersion)
+      domain.present? && token.present? && api_version.is_a?(ApiVersion) && valid_access_scopes?
     end
 
     def expires_in
@@ -181,6 +181,10 @@ def state
 
     private
 
+    def valid_access_scopes?
+      access_scopes.nil? || access_scopes.is_a?(ShopifyAPI::ApiAccess)
+    end
+
     def access_scopes=(access_scopes)
       return unless access_scopes
       @access_scopes = ShopifyAPI::ApiAccess.new(access_scopes)

test/session_test.rb

@@ -54,6 +54,39 @@ def setup
     assert(session.valid?)
   end
 
+  test "be valid with nil access_scopes" do
+    session = ShopifyAPI::Session.new(
+      domain: "testshop.myshopify.com",
+      token: "any-token",
+      api_version: any_api_version,
+      access_scopes: nil
+    )
+
+    assert(session.valid?)
+  end
+
+  test "be valid with string of access_scopes" do
+    session = ShopifyAPI::Session.new(
+      domain: "testshop.myshopify.com",
+      token: "any-token",
+      api_version: any_api_version,
+      access_scopes: "read_products, write_orders"
+    )
+
+    assert(session.valid?)
+  end
+
+  test "be valid with a collection of access_scopes" do
+    session = ShopifyAPI::Session.new(
+      domain: "testshop.myshopify.com",
+      token: "any-token",
+      api_version: any_api_version,
+      access_scopes: %w(read_products write_orders)
+    )
+
+    assert(session.valid?)
+  end
+
   test "not raise error without params" do
     assert_nothing_raised do
       ShopifyAPI::Session.new(domain: "testshop.myshopify.com", token: "any-token", api_version: any_api_version)