created binary_to_decimal and decimal_to_binary methods and testing

Gemfile

@@ -1,6 +1,6 @@
 source 'http://rubygems.org'
 
-ruby '2.6.6'
+ruby '2.6.5'
 
 gem 'rake'
 

lib/binary_to_decimal.rb

@@ -5,5 +5,77 @@
 # Calculate  and return the decimal value for this binary number using
 # the algorithm you devised in class.
 def binary_to_decimal(binary_array)
-  raise NotImplementedError
+  decimal = 0
+  index = 0
+
+  until index == binary_array.length
+    power = (binary_array.length - 1) - index
+
+    decimal += binary_array[index] * ( 2 ** (power))
+
+    index += 1
+  end
+
+  return decimal
 end
+
+
+# Method named decimal_to_binary receives decimal number as input
+# Calculates and returns the binary value as a number for the decimal number
+def decimal_to_binary(decimal)
+  binary = 0
+  power = 0
+
+  if decimal.class == Integer
+    until decimal == 0
+      binary_digit = decimal % 2
+      binary += binary_digit * (10 ** power)
+
+      decimal /= 2
+      power += 1
+    end
+
+    return binary
+  elsif decimal.class == Float
+    decimal_before_dot = decimal - (decimal % 1)
+    binary_before_dot = 0
+
+
+    until decimal_before_dot == 0
+      binary_digit = decimal_before_dot % 2
+      binary_before_dot += binary_digit * (10 ** power)
+
+
+      decimal_before_dot = (decimal_before_dot / 2)
+      decimal_before_dot = decimal_before_dot - (decimal_before_dot % 1)
+
+      power += 1
+    end
+
+
+    decimal_after_dot = (decimal % 1)
+    binary_after_dot_string = "0."
+
+    until decimal_after_dot == 0
+      binary_digit = (decimal_after_dot * 2) - ((decimal_after_dot * 2) % 1)
+
+      if binary_digit == 0
+        binary_after_dot_string << "0"
+      elsif binary_digit == 1
+        binary_after_dot_string << "1"
+      end
+
+      decimal_after_dot = (decimal_after_dot * 2) % 1
+    end
+
+    binary_after_dot = binary_after_dot_string.to_f
+
+
+    binary = binary_before_dot + binary_after_dot
+
+    return binary
+  else # if decimal input is not an integer or float
+    raise ArgumentError, "Not a number."
+  end
+
+end

test/binary_to_decimal_test.rb

@@ -33,3 +33,33 @@
     expect(binary_to_decimal(binary_array)).must_equal expected_decimal
   end
 end
+
+
+describe "decimal to binary" do
+  it "From 0 to 0" do
+    decimal = 0
+    expected_binary = 0
+
+    expect(decimal_to_binary(decimal)).must_equal expected_binary
+  end
+
+  it "From 87 to 1010111" do
+    decimal = 87
+    expected_binary = 1010111
+
+    expect(decimal_to_binary(decimal)).must_equal expected_binary
+  end
+
+  it "From 3.703125 to 11.101101" do
+    decimal = 3.703125
+    expected_binary = 11.101101
+
+    expect(decimal_to_binary(decimal)).must_equal expected_binary
+  end
+
+  it "Raises an ArgumentError if decimal is not a number" do
+    decimal = 'a'
+
+    expect{ decimal_to_binary(decimal) }.must_raise ArgumentError
+  end
+end