1 files changed, 173 insertions, 0 deletions
diff --git a/spec/models/ci/build_dependencies_spec.rb b/spec/models/ci/build_dependencies_spec.rb
new file mode 100644
index 00000000000..6db69d0f34c
--- /dev/null
+++ b/spec/models/ci/build_dependencies_spec.rb
@@ -0,0 +1,173 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Ci::BuildDependencies do
+  let_it_be(:user) { create(:user) }
+  let_it_be(:project, reload: true) { create(:project, :repository) }
+
+  let_it_be(:pipeline, reload: true) do
+    create(:ci_pipeline, project: project,
+                         sha: project.commit.id,
+                         ref: project.default_branch,
+                         status: 'success')
+  end
+
+  let!(:build) { create(:ci_build, pipeline: pipeline, name: 'build', stage_idx: 0, stage: 'build') }
+  let!(:rspec_test) { create(:ci_build, pipeline: pipeline, name: 'rspec', stage_idx: 1, stage: 'test') }
+  let!(:rubocop_test) { create(:ci_build, pipeline: pipeline, name: 'rubocop', stage_idx: 1, stage: 'test') }
+  let!(:staging) { create(:ci_build, pipeline: pipeline, name: 'staging', stage_idx: 2, stage: 'deploy') }
+
+  describe '#local' do
+    subject { described_class.new(job).local }
+
+    describe 'jobs from previous stages' do
+      context 'when job is in the first stage' do
+        let(:job) { build }
+
+        it { is_expected.to be_empty }
+      end
+
+      context 'when job is in the second stage' do
+        let(:job) { rspec_test }
+
+        it 'contains all jobs from the first stage' do
+          is_expected.to contain_exactly(build)
+        end
+      end
+
+      context 'when job is in the last stage' do
+        let(:job) { staging }
+
+        it 'contains all jobs from all previous stages' do
+          is_expected.to contain_exactly(build, rspec_test, rubocop_test)
+        end
+
+        context 'when a job is retried' do
+          before do
+            project.add_developer(user)
+          end
+
+          let(:retried_job) { Ci::Build.retry(rspec_test, user) }
+
+          it 'contains the retried job instead of the original one' do
+            is_expected.to contain_exactly(build, retried_job, rubocop_test)
+          end
+        end
+      end
+    end
+
+    describe 'jobs from specified dependencies' do
+      let(:dependencies) { }
+      let(:needs) { }
+
+      let!(:job) do
+        scheduling_type = needs.present? ? :dag : :stage
+
+        create(:ci_build,
+          pipeline: pipeline,
+          name: 'final',
+          scheduling_type: scheduling_type,
+          stage_idx: 3,
+          stage: 'deploy',
+          options: { dependencies: dependencies }
+        )
+      end
+
+      before do
+        needs.to_a.each do |need|
+          create(:ci_build_need, build: job, **need)
+        end
+      end
+
+      context 'when dependencies are defined' do
+        let(:dependencies) { %w(rspec staging) }
+
+        it { is_expected.to contain_exactly(rspec_test, staging) }
+      end
+
+      context 'when needs are defined' do
+        let(:needs) do
+          [
+            { name: 'build',   artifacts: true },
+            { name: 'rspec',   artifacts: true },
+            { name: 'staging', artifacts: true }
+          ]
+        end
+
+        it { is_expected.to contain_exactly(build, rspec_test, staging) }
+
+        context 'when ci_dag_support is disabled' do
+          before do
+            stub_feature_flags(ci_dag_support: false)
+          end
+
+          it { is_expected.to contain_exactly(build, rspec_test, rubocop_test, staging) }
+        end
+      end
+
+      context 'when need artifacts are defined' do
+        let(:needs) do
+          [
+            { name: 'build',   artifacts: true },
+            { name: 'rspec',   artifacts: false },
+            { name: 'staging', artifacts: true }
+          ]
+        end
+
+        it { is_expected.to contain_exactly(build, staging) }
+      end
+
+      context 'when needs and dependencies are defined' do
+        let(:dependencies) { %w(rspec staging) }
+        let(:needs) do
+          [
+            { name: 'build',   artifacts: true },
+            { name: 'rspec',   artifacts: true },
+            { name: 'staging', artifacts: true }
+          ]
+        end
+
+        it { is_expected.to contain_exactly(rspec_test, staging) }
+      end
+
+      context 'when needs and dependencies contradict' do
+        let(:dependencies) { %w(rspec staging) }
+        let(:needs) do
+          [
+            { name: 'build',   artifacts: true },
+            { name: 'rspec',   artifacts: false },
+            { name: 'staging', artifacts: true }
+          ]
+        end
+
+        it 'returns only the intersection' do
+          is_expected.to contain_exactly(staging)
+        end
+      end
+
+      context 'when nor dependencies or needs are defined' do
+        it 'returns the jobs from previous stages' do
+          is_expected.to contain_exactly(build, rspec_test, rubocop_test, staging)
+        end
+      end
+    end
+  end
+
+  describe '#all' do
+    let!(:job) do
+      create(:ci_build, pipeline: pipeline, name: 'deploy', stage_idx: 3, stage: 'deploy')
+    end
+
+    let(:dependencies) { described_class.new(job) }
+
+    subject { dependencies.all }
+
+    it 'returns the union of all local dependencies and any cross pipeline dependencies' do
+      expect(dependencies).to receive(:local).and_return([1, 2, 3])
+      expect(dependencies).to receive(:cross_pipeline).and_return([3, 4])
+
+      expect(subject).to contain_exactly(1, 2, 3, 4)
+    end
+  end
+end