Remove trailing whitespace

Author: cacheflow

lib/fcm.rb

@@ -295,19 +295,15 @@ def jwt_token
 
   def credentials_error_msg(param)
     error_msg = 'credentials must be an IO-like ' \
-      'object or path '
-    
-    if param.nil?
-      error_msg += 'You passed nil'
-    else 
-      error_msg += "You passed a #{param.class.name}"
-    end
+      'object or path. You passed'
 
+    param_klass = param.nil? ? 'nil' : "a #{param.class.name}"
+    error_msg += " #{param_klass}."
     raise InvalidCredentialError, error_msg
   end
 
   def filename_or_io_like?(path)
-    (path.is_a?(String) || path.respond_to?(:open)) && File.file?(path)
+    (path.is_a?(String) || path.respond_to?(:open)) && File.exists?(path)
   end
 
   def json_key

spec/fcm_spec.rb

@@ -68,17 +68,17 @@
     end
 
     it 'raises an error when passed a non IO-like object' do
-      expect do 
+      expect do
         FCM.new(nil, '', {}).__send__(:json_key)
       end.to raise_error(creds_error, 'credentials must be' \
       ' an IO-like object or path. You passed nil.')
-      
-      expect do 
+
+      expect do
         FCM.new(json_credentials, '', {}).__send__(:json_key) 
       end.to raise_error(creds_error, 'credentials must be' \
       ' an IO-like object or path. You passed a String.')
-      
-      expect do 
+
+      expect do
         FCM.new({}, '', {}).__send__(:json_key)
       end.to raise_error(creds_error, 'credentials must be' \
       ' an IO-like object or path. You passed a Hash.')