1 files changed, 246 insertions, 0 deletions
diff --git a/spec/lib/gitlab/template_parser/ast_spec.rb b/spec/lib/gitlab/template_parser/ast_spec.rb
new file mode 100644
index 00000000000..27361ea8632
--- /dev/null
+++ b/spec/lib/gitlab/template_parser/ast_spec.rb
@@ -0,0 +1,246 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::TemplateParser::AST::Identifier do
+  let(:state) { Gitlab::TemplateParser::EvalState.new }
+
+  describe '#evaluate' do
+    it 'evaluates a selector' do
+      data = { 'number' => 10 }
+
+      expect(described_class.new('number').evaluate(state, data)).to eq(10)
+    end
+
+    it 'returns nil if the key is not set' do
+      expect(described_class.new('number').evaluate(state, {})).to be_nil
+    end
+
+    it 'returns nil if the input is not a Hash' do
+      expect(described_class.new('number').evaluate(state, 45)).to be_nil
+    end
+
+    it 'returns the current data when using the special identifier "it"' do
+      expect(described_class.new('it').evaluate(state, 45)).to eq(45)
+    end
+  end
+end
+
+RSpec.describe Gitlab::TemplateParser::AST::Integer do
+  let(:state) { Gitlab::TemplateParser::EvalState.new }
+
+  describe '#evaluate' do
+    it 'evaluates a selector' do
+      expect(described_class.new(0).evaluate(state, [10])).to eq(10)
+    end
+
+    it 'returns nil if the index is not set' do
+      expect(described_class.new(1).evaluate(state, [10])).to be_nil
+    end
+
+    it 'returns nil if the input is not an Array' do
+      expect(described_class.new(0).evaluate(state, {})).to be_nil
+    end
+  end
+end
+
+RSpec.describe Gitlab::TemplateParser::AST::Selector do
+  let(:state) { Gitlab::TemplateParser::EvalState.new }
+  let(:data) { { 'numbers' => [10] } }
+
+  describe '#evaluate' do
+    it 'evaluates a selector' do
+      ident = Gitlab::TemplateParser::AST::Identifier.new('numbers')
+      int = Gitlab::TemplateParser::AST::Integer.new(0)
+
+      expect(described_class.new([ident, int]).evaluate(state, data)).to eq(10)
+    end
+
+    it 'evaluates a selector that returns nil' do
+      int = Gitlab::TemplateParser::AST::Integer.new(0)
+
+      expect(described_class.new([int]).evaluate(state, data)).to be_nil
+    end
+  end
+end
+
+RSpec.describe Gitlab::TemplateParser::AST::Variable do
+  let(:state) { Gitlab::TemplateParser::EvalState.new }
+  let(:data) { { 'numbers' => [10] } }
+
+  describe '#evaluate' do
+    it 'evaluates a variable' do
+      node = Gitlab::TemplateParser::Parser
+        .new
+        .parse_and_transform('{{numbers.0}}')
+        .nodes[0]
+
+      expect(node.evaluate(state, data)).to eq('10')
+    end
+
+    it 'evaluates an undefined variable' do
+      node =
+        Gitlab::TemplateParser::Parser.new.parse_and_transform('{{foobar}}').nodes[0]
+
+      expect(node.evaluate(state, data)).to eq('')
+    end
+
+    it 'evaluates the special variable "it"' do
+      node =
+        Gitlab::TemplateParser::Parser.new.parse_and_transform('{{it}}').nodes[0]
+
+      expect(node.evaluate(state, data)).to eq(data.to_s)
+    end
+  end
+end
+
+RSpec.describe Gitlab::TemplateParser::AST::Expressions do
+  let(:state) { Gitlab::TemplateParser::EvalState.new }
+
+  describe '#evaluate' do
+    it 'evaluates all expressions' do
+      node = Gitlab::TemplateParser::Parser
+        .new
+        .parse_and_transform('{{number}}foo')
+
+      expect(node.evaluate(state, { 'number' => 10 })).to eq('10foo')
+    end
+  end
+end
+
+RSpec.describe Gitlab::TemplateParser::AST::Text do
+  let(:state) { Gitlab::TemplateParser::EvalState.new }
+
+  describe '#evaluate' do
+    it 'returns the text' do
+      expect(described_class.new('foo').evaluate(state, {})).to eq('foo')
+    end
+  end
+end
+
+RSpec.describe Gitlab::TemplateParser::AST::If do
+  let(:state) { Gitlab::TemplateParser::EvalState.new }
+
+  describe '#evaluate' do
+    it 'evaluates a truthy if expression without an else clause' do
+      node = Gitlab::TemplateParser::Parser
+        .new
+        .parse_and_transform('{% if thing %}foo{% end %}')
+        .nodes[0]
+
+      expect(node.evaluate(state, { 'thing' => true })).to eq('foo')
+    end
+
+    it 'evaluates a falsy if expression without an else clause' do
+      node = Gitlab::TemplateParser::Parser
+        .new
+        .parse_and_transform('{% if thing %}foo{% end %}')
+        .nodes[0]
+
+      expect(node.evaluate(state, { 'thing' => false })).to eq('')
+    end
+
+    it 'evaluates a falsy if expression with an else clause' do
+      node = Gitlab::TemplateParser::Parser
+        .new
+        .parse_and_transform('{% if thing %}foo{% else %}bar{% end %}')
+        .nodes[0]
+
+      expect(node.evaluate(state, { 'thing' => false })).to eq('bar')
+    end
+  end
+
+  describe '#truthy?' do
+    it 'returns true for a non-empty String' do
+      expect(described_class.new.truthy?('foo')).to eq(true)
+    end
+
+    it 'returns true for a non-empty Array' do
+      expect(described_class.new.truthy?([10])).to eq(true)
+    end
+
+    it 'returns true for a Boolean true' do
+      expect(described_class.new.truthy?(true)).to eq(true)
+    end
+
+    it 'returns false for an empty String' do
+      expect(described_class.new.truthy?('')).to eq(false)
+    end
+
+    it 'returns true for an empty Array' do
+      expect(described_class.new.truthy?([])).to eq(false)
+    end
+
+    it 'returns false for a Boolean false' do
+      expect(described_class.new.truthy?(false)).to eq(false)
+    end
+  end
+end
+
+RSpec.describe Gitlab::TemplateParser::AST::Each do
+  let(:state) { Gitlab::TemplateParser::EvalState.new }
+
+  describe '#evaluate' do
+    it 'evaluates the expression' do
+      data = { 'animals' => [{ 'name' => 'Cat' }, { 'name' => 'Dog' }] }
+      node = Gitlab::TemplateParser::Parser
+        .new
+        .parse_and_transform('{% each animals %}{{name}}{% end %}')
+        .nodes[0]
+
+      expect(node.evaluate(state, data)).to eq('CatDog')
+    end
+
+    it 'returns an empty string when the input is not a collection' do
+      data = { 'animals' => 10 }
+      node = Gitlab::TemplateParser::Parser
+        .new
+        .parse_and_transform('{% each animals %}{{name}}{% end %}')
+        .nodes[0]
+
+      expect(node.evaluate(state, data)).to eq('')
+    end
+
+    it 'disallows too many nested loops' do
+      data = {
+        'foo' => [
+          {
+            'bar' => [
+              {
+                'baz' => [
+                  {
+                    'quix' => [
+                      {
+                        'foo' => [{ 'name' => 'Alice' }]
+                      }
+                    ]
+                  }
+                ]
+              }
+            ]
+          }
+        ]
+      }
+
+      template = <<~TPL
+        {% each foo %}
+          {% each bar %}
+            {% each baz %}
+              {% each quix %}
+                {% each foo %}
+                  {{name}}
+                {% end %}
+              {% end %}
+            {% end %}
+          {% end %}
+        {% end %}
+      TPL
+
+      node =
+        Gitlab::TemplateParser::Parser.new.parse_and_transform(template).nodes[0]
+
+      expect { node.evaluate(state, data) }
+        .to raise_error(Gitlab::TemplateParser::Error)
+    end
+  end
+end