add tests

test/models/comment_test.rb

@@ -1,7 +1,29 @@
 require "test_helper"
 
 class CommentTest < ActiveSupport::TestCase
-  # test "the truth" do
-  #   assert true
-  # end
+  test "should be valid with a user, body, and commentable" do
+    user = users(:one)
+    entry = entries(:one)
+    comment = Comment.new(user: user, body: "This is a comment.", commentable: entry)
+    assert comment.valid?
+  end
+
+  test "should be invalid without a body" do
+    user = users(:one)
+    entry = entries(:one)
+    comment = Comment.new(user: user, commentable: entry)
+    assert_not comment.valid?
+  end
+
+  test "should be invalid without a user" do
+    entry = entries(:one)
+    comment = Comment.new(body: "This is a comment.", commentable: entry)
+    assert_not comment.valid?
+  end
+
+  test "should be invalid without a commentable" do
+    user = users(:one)
+    comment = Comment.new(user: user, body: "This is a comment.")
+    assert_not comment.valid?
+  end
 end