diff --git a/spec/migrations/20170530102630_clean_up_duplicates_in_containers_tables_spec.rb b/spec/migrations/20170530102630_clean_up_duplicates_in_containers_tables_spec.rb
new file mode 100644
index 000000000..6cdf3f370
--- /dev/null
+++ b/spec/migrations/20170530102630_clean_up_duplicates_in_containers_tables_spec.rb
@@ -0,0 +1,131 @@
+require_migration
+
+describe CleanUpDuplicatesInContainersTables do
+  def model_unique_keys(model)
+    models[model]
+  end
+
+  def models
+    described_class::UNIQUE_INDEXES_FOR_MODELS
+  end
+
+  def model_stub(model)
+    migration_stub(model.to_s.to_sym)
+  end
+
+  def create_test_data(model)
+    build_data(model, 10, "string_1")
+    build_data(model, 10, "string_1")
+    build_data(model, 10, "string_2")
+    build_data(model, 11, "string_1")
+    build_data(model, 11, "string_1")
+    build_data(model, 11, "string_1")
+    build_data(model, 11, "string_1")
+    build_data(model, 12, "string_1")
+    build_data(model, nil, "string_1")
+    build_data(model, nil, "string_1")
+  end
+
+  def build_data(model, foreign_key_value, string_value)
+    data_values = model_unique_keys(model).each_with_object({}) do |key, obj|
+      obj[key] = build_value(key, foreign_key_value, string_value)
+    end
+    model.create!(data_values)
+  end
+
+  def build_value(key, foreign_key_value, string_value)
+    if key.to_s.ends_with?("id")
+      foreign_key_value
+    else
+      string_value
+    end
+  end
+
+  def analyze(model)
+    original_values = {}
+    duplicate_values = {}
+    model.all.each do |record|
+      index = record.attributes.symbolize_keys.slice(*model_unique_keys(model))
+      if original_values[index]
+        duplicate_values[index] << record.id
+      else
+        original_values[index] = record.id
+        duplicate_values[index] ||= []
+      end
+    end
+
+    return original_values, duplicate_values
+  end
+
+  def assert_before_migration_test_data(model, original_values, duplicate_values)
+    expect(model.count).to eq(10)
+
+    # Check there are 5 duplicates in the data
+    expect(original_values.count).to eq(5)
+    expect(duplicate_values.count).to eq(5)
+
+    # Check that original values ids are the min or all duplicated ids
+    original_values.each do |key, value|
+      expect((duplicate_values[key] << value).min).to eq value
+    end
+  end
+
+  def assert_after_migration_test_data(model, original_values, duplicate_values)
+    expect(model.count).to eq(5)
+
+    model.all.each do |record|
+      expect(original_values[record.attributes.symbolize_keys.slice(*model_unique_keys(model))]).to eq record.id
+    end
+  end
+
+  migration_context :up do
+    it "manually checks we clean up duplicates in ContainerBuild build model" do
+      model = CleanUpDuplicatesInContainersTables::ContainerBuild
+      create_test_data(model)
+
+      expect(model.pluck(*model_unique_keys(model))).to(
+        match_array(
+          [
+            [10, "string_1"],
+            [10, "string_1"],
+            [10, "string_2"],
+            [11, "string_1"],
+            [11, "string_1"],
+            [11, "string_1"],
+            [11, "string_1"],
+            [12, "string_1"],
+            [nil, "string_1"],
+            [nil, "string_1"]
+          ]
+        )
+      )
+
+      migrate
+
+      expect(model.pluck(*model_unique_keys(model))).to(
+        match_array(
+          [
+            [10, "string_1"],
+            [10, "string_2"],
+            [11, "string_1"],
+            [12, "string_1"],
+            [nil, "string_1"]
+          ]
+        )
+      )
+    end
+
+    described_class::UNIQUE_INDEXES_FOR_MODELS.keys.each do |model|
+      context "with model #{model}" do
+        it "checks that the duplicate values are cleaned up" do
+          create_test_data(model)
+
+          original_values, duplicate_values = analyze(model)
+          assert_before_migration_test_data(model, original_values, duplicate_values)
+          migrate
+          assert_after_migration_test_data(model, original_values, duplicate_values)
+        end
+      end
+    end
+  end
+end