implement number factorization

app/controller/primes.rb

@@ -15,7 +15,7 @@ def decompose(input)
     if !(Integer(input) rescue false)
       PrimeResults::NotANumber.new(input)
     else
-      PrimeResults::Valid.new(input, PrimeFactors.factorsOf(input.to_i))
+      PrimeResults::Valid.new(input, PrimeFactors.of(input.to_i))
     end
   end
 

app/primes/prime_factors.rb

@@ -1,13 +1,15 @@
 class PrimeFactors
 
-  def self.factorsOf(number)
+  def self.of(number)
     primes = []
 
-    if number > 1
-      while number % 2 == 0
-        primes << 2
-        number /= 2
+    candidate = 2
+    while number > 1
+      while number % candidate == 0
+        primes << candidate
+        number /= candidate
       end
+      candidate += 1
     end
 
     primes

spec/challenges/prime_factors_challenge_spec.rb

@@ -32,4 +32,16 @@ def app
         '}')
   end
 
+  it "decomposes a positive integer into prime factors" do
+    get "/primeFactors?number=300"
+
+    expect(last_response.status).to eq(200)
+    expect(last_response.content_type).to eq("application/json")
+    expect(last_response.body).to eq(
+        '{' \
+          '"number":300,' \
+          '"decomposition":[2,2,3,5,5]' \
+        '}')
+  end
+
 end

spec/primes/prime_factors_spec.rb

@@ -3,19 +3,27 @@
 RSpec.describe "Prime Factors" do
 
   it 'returns empty for number lower than 2' do
-    expect(PrimeFactors.factorsOf(1)).to be_empty
+    expect(PrimeFactors.of(1)).to be_empty
   end
 
   it 'decomposes 2' do
-    expect(PrimeFactors.factorsOf(2)).to eq [2]
+    expect(PrimeFactors.of(2)).to eq [2]
   end
 
   it 'decomposes 4' do
-    expect(PrimeFactors.factorsOf(4)).to eq [2, 2]
+    expect(PrimeFactors.of(4)).to eq [2, 2]
   end
 
   it 'decomposes 32' do
-    expect(PrimeFactors.factorsOf(32)).to eq [2, 2, 2, 2, 2]
+    expect(PrimeFactors.of(32)).to eq [2, 2, 2, 2, 2]
+  end
+
+  it 'decomposes 25' do
+    expect(PrimeFactors.of(25)).to eq [5,5]
+  end
+
+  it 'decomposes 50' do
+    expect(PrimeFactors.of(50)).to eq [2,5,5]
   end
 
 end