diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4ebc8ae
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+coverage
diff --git a/lib/blackjack_score.rb b/lib/blackjack_score.rb
index fca19e0..a7c4bb7 100644
--- a/lib/blackjack_score.rb
+++ b/lib/blackjack_score.rb
@@ -3,5 +3,35 @@
 VALID_CARDS = [2, 3, 4, 5, 6, 7, 8, 9, 10, 'Jack', 'Queen', 'King', 'Ace']
 
 def blackjack_score(hand)
+    score = 0
+    ace_count = 0
+    hand.each do |card|
+      unless VALID_CARDS.include?(card)
+        raise ArgumentError.new("#{card} is invalid")
+      end
 
+      case card
+      when 'Jack', 'Queen', 'King'
+        score += 10
+      when 'Ace'
+        ace_count += 1
+        score += 11
+      else
+        score += card
+      end
+    end
+
+    while score > 21 && ace_count > 0
+      score -= 10
+      ace_count -= 1
+    end
+
+    if score > 21
+      raise ArgumentError.new("Bust! Score is over 21")
+    end
+
+    return score
 end
+
+# Maybe I should create a separate variable for ace?
+
diff --git a/test/blackjack_score_test.rb b/test/blackjack_score_test.rb
index 3175a82..89e7a4b 100644
--- a/test/blackjack_score_test.rb
+++ b/test/blackjack_score_test.rb
@@ -3,6 +3,8 @@
 require 'minitest/autorun'
 require 'minitest/reporters'
 require 'minitest/pride'
+# require 'simplecov'
+# SimpleCov.start
 
 require_relative '../lib/blackjack_score'
 
@@ -18,26 +20,45 @@
     score = blackjack_score(hand)
 
     # Assert <-  You do this part!
+    expect(score).must_equal 7
 
   end
 
   it 'facecards have values calculated correctly' do
 
+    hand = ['Jack', 3, 5]
+    score = blackjack_score(hand)
+    expect(score).must_equal 18
+
   end
 
   it 'calculates aces as 11 where it does not go over 21' do
-
+    hand = ['Ace', 7]
+    score = blackjack_score(hand)
+    expect(score).must_equal 18
   end
 
   it 'calculates aces as 1, if an 11 would cause the score to go over 21' do
+    hand = ['Ace', 5, 9]
+    score = blackjack_score(hand)
+    expect(score).must_equal 15
 
   end
 
   it 'raises an ArgumentError for invalid cards' do
+    hand = ['poker', 2]
 
+    expect {
+      blackjack_score(hand)
+    }.must_raise ArgumentError
   end
 
   it 'raises an ArgumentError for scores over 21' do
+    hand = [10, 10, 3]
+
+    expect {
+      blackjack_score(hand)
+    }.must_raise ArgumentError
 
   end
 end