1 files changed, 102 insertions, 0 deletions
diff --git a/spec/lib/gitlab/ci/config/interpolation/template_spec.rb b/spec/lib/gitlab/ci/config/interpolation/template_spec.rb
new file mode 100644
index 00000000000..c7d88822558
--- /dev/null
+++ b/spec/lib/gitlab/ci/config/interpolation/template_spec.rb
@@ -0,0 +1,102 @@
+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+
+RSpec.describe Gitlab::Ci::Config::Interpolation::Template, feature_category: :pipeline_composition do
+  subject { described_class.new(YAML.safe_load(config), ctx) }
+
+  let(:config) do
+    <<~CFG
+    test:
+      spec:
+        env: $[[ inputs.env ]]
+
+    $[[ inputs.key ]]:
+      name: $[[ inputs.key ]]
+      script: my-value
+    CFG
+  end
+
+  let(:ctx) do
+    { inputs: { env: 'dev', key: 'abc' } }
+  end
+
+  it 'collects interpolation blocks' do
+    expect(subject.size).to eq 2
+  end
+
+  it 'interpolates the values properly' do
+    expect(subject.interpolated).to eq YAML.safe_load <<~RESULT
+    test:
+      spec:
+        env: dev
+
+    abc:
+      name: abc
+      script: my-value
+    RESULT
+  end
+
+  context 'when interpolation can not be performed' do
+    let(:config) { '$[[ xxx.yyy ]]: abc' }
+
+    it 'does not interpolate the config' do
+      expect(subject).not_to be_valid
+      expect(subject.interpolated).to be_nil
+    end
+  end
+
+  context 'when template consists of nested arrays with hashes and values' do
+    let(:config) do
+      <<~CFG
+      test:
+        - a-$[[ inputs.key ]]-b
+        - c-$[[ inputs.key ]]-d:
+            d-$[[ inputs.key ]]-e
+          val: 1
+      CFG
+    end
+
+    it 'performs a valid interpolation' do
+      result = { 'test' => ['a-abc-b', { 'c-abc-d' => 'd-abc-e', 'val' => 1 }] }
+
+      expect(subject).to be_valid
+      expect(subject.interpolated).to eq result
+    end
+  end
+
+  context 'when template contains symbols that need interpolation' do
+    subject do
+      described_class.new({ '$[[ inputs.key ]]': 'cde' }, ctx)
+    end
+
+    it 'performs a valid interpolation' do
+      expect(subject).to be_valid
+      expect(subject.interpolated).to eq({ 'abc' => 'cde' })
+    end
+  end
+
+  context 'when template is too large' do
+    before do
+      stub_const('Gitlab::Ci::Config::Interpolation::Config::MAX_NODES', 1)
+    end
+
+    it 'returns an error' do
+      expect(subject.interpolated).to be_nil
+      expect(subject.errors.count).to eq 1
+      expect(subject.errors.first).to eq 'config too large'
+    end
+  end
+
+  context 'when there are too many interpolation blocks' do
+    before do
+      stub_const("#{described_class}::MAX_BLOCKS", 1)
+    end
+
+    it 'returns an error' do
+      expect(subject.interpolated).to be_nil
+      expect(subject.errors.count).to eq 1
+      expect(subject.errors.first).to eq 'too many interpolation blocks'
+    end
+  end
+end