Add molecule_id to samples. Sample belong to molecule. Molecule has many samples

Check SHA of a loaded file with a stored file

app/models/molecule.rb

 class Molecule < ActiveRecord::Base
-  belongs_to :sample
+  has_many :samples
 
   validates_uniqueness_of :inchikey
 end

app/models/sample.rb

@@ -9,6 +9,8 @@ class Sample < ActiveRecord::Base
   has_many :reactions_as_starting_material, through: :reactions_starting_material_samples, source: :reaction
   has_many :reactions_as_reactant, through: :reactions_reactant_samples, source: :reaction
   has_many :reactions_as_product, through: :reactions_product_samples, source: :reaction
+
+  belongs_to :molecule
   
   composed_of :amount, mapping: %w(amount_value, amount_unit)
 end

db/migrate/20150817200859_create_molecules.rb

 class CreateMolecules < ActiveRecord::Migration
   def change
     create_table :molecules do |t|
-      t.integer :sample_id
       t.string :inchikey
       t.string :inchistring
       t.float :density

db/migrate/20150818100730_add_molecule_id_to_samples.rb

+class AddMoleculeIdToSamples < ActiveRecord::Migration
+  def change
+    add_column :samples, :molecule_id, :integer
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20150817200859) do
+ActiveRecord::Schema.define(version: 20150818100730) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -105,6 +105,7 @@ ActiveRecord::Schema.define(version: 20150817200859) do
     t.datetime "created_at",                null: false
     t.datetime "updated_at",                null: false
     t.text     "description",  default: ""
+    t.integer  "molecule_id"
   end
 
   create_table "users", force: :cascade do |t|

spec/models/molecule_spec.rb

@@ -27,14 +27,16 @@ RSpec.describe Molecule, type: :model do
     end
 
     it 'should persist the binary molfile' do
-      molecule.molfile = 
-        (Digest::SHA256.new << "Example Binary Molefile Content").hexdigest
+      molfile_example = File.open("spec/models/molecule_spec.rb", "rb")
+      molecule.molfile = molfile_example.read
+      molfile_example.close
       molecule.save
       persisted_molecule = Molecule.last
-      expect(persisted_molecule.molfile).to be === (molecule.molfile)
+      persisted_molfile_SHA =
+        (Digest::SHA256.new << persisted_molecule.molfile).hexdigest
+      molfile_SHA =
+        (Digest::SHA256.new << molecule.molfile).hexdigest
+      expect(persisted_molfile_SHA).to be === (molfile_SHA)
     end
   end
-
-  # concern "with sample"
-    # it should belong to a sample
 end

spec/models/sample_spec.rb

@@ -11,4 +11,18 @@ RSpec.describe Sample, type: :model do
 
 
 
+  context 'with molecule' do
+
+    let(:sample) { build(:sample) }
+    let(:molecule) {create(:molecule)}
+
+    it 'it should belong to a sample' do
+      sample.molecule = molecule
+      sample.save
+
+      persisted_sample = Sample.last
+      expect(persisted_sample.molecule).to be === (molecule)
+    end
+  end
+
 end