Merge branch 'feature/gb/pipeline-variable-expressions' into 'master'

Pipeline variables expressions

See merge request gitlab-org/gitlab-ce!17261

8 files changed, 423 insertions, 0 deletions

diff --git a/spec/lib/gitlab/ci/pipeline/expression/lexeme/equals_spec.rb b/spec/lib/gitlab/ci/pipeline/expression/lexeme/equals_spec.rb
new file mode 100644
index 00000000000..019a2ed184d
--- /dev/null
+++ b/spec/lib/gitlab/ci/pipeline/expression/lexeme/equals_spec.rb
@@ -0,0 +1,39 @@
+require 'spec_helper'
+
+describe Gitlab::Ci::Pipeline::Expression::Lexeme::Equals do
+  let(:left) { double('left') }
+  let(:right) { double('right') }
+
+  describe '.build' do
+    it 'creates a new instance of the token' do
+      expect(described_class.build('==', left, right))
+        .to be_a(described_class)
+    end
+  end
+
+  describe '.type' do
+    it 'is an operator' do
+      expect(described_class.type).to eq :operator
+    end
+  end
+
+  describe '#evaluate' do
+    it 'returns false when left and right are not equal' do
+      allow(left).to receive(:evaluate).and_return(1)
+      allow(right).to receive(:evaluate).and_return(2)
+
+      operator = described_class.new(left, right)
+
+      expect(operator.evaluate(VARIABLE: 3)).to eq false
+    end
+
+    it 'returns true when left and right are equal' do
+      allow(left).to receive(:evaluate).and_return(1)
+      allow(right).to receive(:evaluate).and_return(1)
+
+      operator = described_class.new(left, right)
+
+      expect(operator.evaluate(VARIABLE: 3)).to eq true
+    end
+  end
+end
diff --git a/spec/lib/gitlab/ci/pipeline/expression/lexeme/null_spec.rb b/spec/lib/gitlab/ci/pipeline/expression/lexeme/null_spec.rb
new file mode 100644
index 00000000000..b5a59929e11
--- /dev/null
+++ b/spec/lib/gitlab/ci/pipeline/expression/lexeme/null_spec.rb
@@ -0,0 +1,22 @@
+require 'spec_helper'
+
+describe Gitlab::Ci::Pipeline::Expression::Lexeme::Null do
+  describe '.build' do
+    it 'creates a new instance of the token' do
+      expect(described_class.build('null'))
+        .to be_a(described_class)
+    end
+  end
+
+  describe '.type' do
+    it 'is a value lexeme' do
+      expect(described_class.type).to eq :value
+    end
+  end
+
+  describe '#evaluate' do
+    it 'always evaluates to `nil`' do
+      expect(described_class.new('null').evaluate).to be_nil
+    end
+  end
+end
diff --git a/spec/lib/gitlab/ci/pipeline/expression/lexeme/string_spec.rb b/spec/lib/gitlab/ci/pipeline/expression/lexeme/string_spec.rb
new file mode 100644
index 00000000000..86234dfb9e5
--- /dev/null
+++ b/spec/lib/gitlab/ci/pipeline/expression/lexeme/string_spec.rb
@@ -0,0 +1,92 @@
+require 'spec_helper'
+
+describe Gitlab::Ci::Pipeline::Expression::Lexeme::String do
+  describe '.build' do
+    it 'creates a new instance of the token' do
+      expect(described_class.build('"my string"'))
+        .to be_a(described_class)
+    end
+  end
+
+  describe '.type' do
+    it 'is a value lexeme' do
+      expect(described_class.type).to eq :value
+    end
+  end
+
+  describe '.scan' do
+    context 'when using double quotes' do
+      it 'correctly identifies string token' do
+        scanner = StringScanner.new('"some string"')
+
+        token = described_class.scan(scanner)
+
+        expect(token).not_to be_nil
+        expect(token.build.evaluate).to eq 'some string'
+      end
+    end
+
+    context 'when using single quotes' do
+      it 'correctly identifies string token' do
+        scanner = StringScanner.new("'some string 2'")
+
+        token = described_class.scan(scanner)
+
+        expect(token).not_to be_nil
+        expect(token.build.evaluate).to eq 'some string 2'
+      end
+    end
+
+    context 'when there are mixed quotes in the string' do
+      it 'is a greedy scanner for double quotes' do
+        scanner = StringScanner.new('"some string" "and another one"')
+
+        token = described_class.scan(scanner)
+
+        expect(token).not_to be_nil
+        expect(token.build.evaluate).to eq 'some string'
+      end
+
+      it 'is a greedy scanner for single quotes' do
+        scanner = StringScanner.new("'some string' 'and another one'")
+
+        token = described_class.scan(scanner)
+
+        expect(token).not_to be_nil
+        expect(token.build.evaluate).to eq 'some string'
+      end
+
+      it 'allows to use single quotes inside double quotes' do
+        scanner = StringScanner.new(%("some ' string"))
+
+        token = described_class.scan(scanner)
+
+        expect(token).not_to be_nil
+        expect(token.build.evaluate).to eq "some ' string"
+      end
+
+      it 'allow to use double quotes inside single quotes' do
+        scanner = StringScanner.new(%('some " string'))
+
+        token = described_class.scan(scanner)
+
+        expect(token).not_to be_nil
+        expect(token.build.evaluate).to eq 'some " string'
+      end
+    end
+  end
+
+  describe '#evaluate' do
+    it 'returns string value it is is present' do
+      string = described_class.new('my string')
+
+      expect(string.evaluate).to eq 'my string'
+    end
+
+    it 'returns an empty string if it is empty' do
+      string = described_class.new('')
+
+      expect(string.evaluate).to eq ''
+    end
+  end
+end
diff --git a/spec/lib/gitlab/ci/pipeline/expression/lexeme/variable_spec.rb b/spec/lib/gitlab/ci/pipeline/expression/lexeme/variable_spec.rb
new file mode 100644
index 00000000000..599a5411881
--- /dev/null
+++ b/spec/lib/gitlab/ci/pipeline/expression/lexeme/variable_spec.rb
@@ -0,0 +1,44 @@
+require 'spec_helper'
+
+describe Gitlab::Ci::Pipeline::Expression::Lexeme::Variable do
+  describe '.build' do
+    it 'creates a new instance of the token' do
+      expect(described_class.build('$VARIABLE'))
+        .to be_a(described_class)
+    end
+  end
+
+  describe '.type' do
+    it 'is a value lexeme' do
+      expect(described_class.type).to eq :value
+    end
+  end
+
+  describe '#evaluate' do
+    it 'returns variable value if it is defined' do
+      variable = described_class.new('VARIABLE')
+
+      expect(variable.evaluate(VARIABLE: 'my variable'))
+        .to eq 'my variable'
+    end
+
+    it 'allows to use a string as a variable key too' do
+      variable = described_class.new('VARIABLE')
+
+      expect(variable.evaluate('VARIABLE' => 'my variable'))
+        .to eq 'my variable'
+    end
+
+    it 'returns nil if it is not defined' do
+      variable = described_class.new('VARIABLE')
+
+      expect(variable.evaluate(OTHER: 'variable')).to be_nil
+    end
+
+    it 'returns an empty string if it is empty' do
+      variable = described_class.new('VARIABLE')
+
+      expect(variable.evaluate(VARIABLE: '')).to eq ''
+    end
+  end
+end
diff --git a/spec/lib/gitlab/ci/pipeline/expression/lexer_spec.rb b/spec/lib/gitlab/ci/pipeline/expression/lexer_spec.rb
new file mode 100644
index 00000000000..230ceeb07f8
--- /dev/null
+++ b/spec/lib/gitlab/ci/pipeline/expression/lexer_spec.rb
@@ -0,0 +1,70 @@
+require 'spec_helper'
+
+describe Gitlab::Ci::Pipeline::Expression::Lexer do
+  let(:token_class) do
+    Gitlab::Ci::Pipeline::Expression::Token
+  end
+
+  describe '#tokens' do
+    it 'tokenss single value' do
+      tokens = described_class.new('$VARIABLE').tokens
+
+      expect(tokens).to be_one
+      expect(tokens).to all(be_an_instance_of(token_class))
+    end
+
+    it 'does ignore whitespace characters' do
+      tokens = described_class.new("\t$VARIABLE ").tokens
+
+      expect(tokens).to be_one
+      expect(tokens).to all(be_an_instance_of(token_class))
+    end
+
+    it 'tokenss multiple values of the same token' do
+      tokens = described_class.new("$VARIABLE1 $VARIABLE2").tokens
+
+      expect(tokens.size).to eq 2
+      expect(tokens).to all(be_an_instance_of(token_class))
+    end
+
+    it 'tokenss multiple values with different tokens' do
+      tokens = described_class.new('$VARIABLE "text" "value"').tokens
+
+      expect(tokens.size).to eq 3
+      expect(tokens.first.value).to eq '$VARIABLE'
+      expect(tokens.second.value).to eq '"text"'
+      expect(tokens.third.value).to eq '"value"'
+    end
+
+    it 'tokenss tokens and operators' do
+      tokens = described_class.new('$VARIABLE == "text"').tokens
+
+      expect(tokens.size).to eq 3
+      expect(tokens.first.value).to eq '$VARIABLE'
+      expect(tokens.second.value).to eq '=='
+      expect(tokens.third.value).to eq '"text"'
+    end
+
+    it 'limits statement to specified amount of tokens' do
+      lexer = described_class.new("$V1 $V2 $V3 $V4", max_tokens: 3)
+
+      expect { lexer.tokens }
+        .to raise_error described_class::SyntaxError
+    end
+
+    it 'raises syntax error in case of finding unknown tokens' do
+      lexer = described_class.new('$V1 123 $V2')
+
+      expect { lexer.tokens }
+        .to raise_error described_class::SyntaxError
+    end
+  end
+
+  describe '#lexemes' do
+    it 'returns an array of syntax lexemes' do
+      lexer = described_class.new('$VAR "text"')
+
+      expect(lexer.lexemes).to eq %w[variable string]
+    end
+  end
+end
diff --git a/spec/lib/gitlab/ci/pipeline/expression/parser_spec.rb b/spec/lib/gitlab/ci/pipeline/expression/parser_spec.rb
new file mode 100644
index 00000000000..e8e6f585310
--- /dev/null
+++ b/spec/lib/gitlab/ci/pipeline/expression/parser_spec.rb
@@ -0,0 +1,26 @@
+require 'spec_helper'
+
+describe Gitlab::Ci::Pipeline::Expression::Parser do
+  describe '#tree' do
+    context 'when using operators' do
+      it 'returns a reverse descent parse tree' do
+        expect(described_class.seed('$VAR1 == "123" == $VAR2').tree)
+          .to be_a Gitlab::Ci::Pipeline::Expression::Lexeme::Equals
+      end
+    end
+
+    context 'when using a single token' do
+      it 'returns a single token instance' do
+        expect(described_class.seed('$VAR').tree)
+          .to be_a Gitlab::Ci::Pipeline::Expression::Lexeme::Variable
+      end
+    end
+
+    context 'when expression is empty' do
+      it 'returns a null token' do
+        expect(described_class.seed('').tree)
+          .to be_a Gitlab::Ci::Pipeline::Expression::Lexeme::Null
+      end
+    end
+  end
+end
diff --git a/spec/lib/gitlab/ci/pipeline/expression/statement_spec.rb b/spec/lib/gitlab/ci/pipeline/expression/statement_spec.rb
new file mode 100644
index 00000000000..472a58599d8
--- /dev/null
+++ b/spec/lib/gitlab/ci/pipeline/expression/statement_spec.rb
@@ -0,0 +1,85 @@
+require 'spec_helper'
+
+describe Gitlab::Ci::Pipeline::Expression::Statement do
+  let(:pipeline) { build(:ci_pipeline) }
+
+  subject do
+    described_class.new(text, pipeline)
+  end
+
+  before do
+    pipeline.variables.build([key: 'VARIABLE', value: 'my variable'])
+  end
+
+  describe '#parse_tree' do
+    context 'when expression is empty' do
+      let(:text) { '' }
+
+      it 'raises an error' do
+        expect { subject.parse_tree }
+          .to raise_error described_class::StatementError
+      end
+    end
+
+    context 'when expression grammar is incorrect' do
+      table = [
+        '$VAR "text"',      # missing operator
+        '== "123"',         # invalid right side
+        "'single quotes'",  # single quotes string
+        '$VAR ==',          # invalid right side
+        '12345',            # unknown syntax
+        ''                  # empty statement
+      ]
+
+      table.each do |syntax|
+        it "raises an error when syntax is `#{syntax}`" do
+          expect { described_class.new(syntax, pipeline).parse_tree }
+            .to raise_error described_class::StatementError
+        end
+      end
+    end
+
+    context 'when expression grammar is correct' do
+      context 'when using an operator' do
+        let(:text) { '$VAR == "value"' }
+
+        it 'returns a reverse descent parse tree' do
+          expect(subject.parse_tree)
+            .to be_a Gitlab::Ci::Pipeline::Expression::Lexeme::Equals
+        end
+      end
+
+      context 'when using a single token' do
+        let(:text) { '$VARIABLE' }
+
+        it 'returns a single token instance' do
+          expect(subject.parse_tree)
+            .to be_a Gitlab::Ci::Pipeline::Expression::Lexeme::Variable
+        end
+      end
+    end
+  end
+
+  describe '#evaluate' do
+    statements = [
+      ['$VARIABLE == "my variable"', true],
+      ["$VARIABLE == 'my variable'", true],
+      ['"my variable" == $VARIABLE', true],
+      ['$VARIABLE == null', false],
+      ['$VAR == null', true],
+      ['null == $VAR', true],
+      ['$VARIABLE', 'my variable'],
+      ['$VAR', nil]
+    ]
+
+    statements.each do |expression, value|
+      context "when using expression `#{expression}`" do
+        let(:text) { expression }
+
+        it "evaluates to `#{value.inspect}`" do
+          expect(subject.evaluate).to eq value
+        end
+      end
+    end
+  end
+end
diff --git a/spec/lib/gitlab/ci/pipeline/expression/token_spec.rb b/spec/lib/gitlab/ci/pipeline/expression/token_spec.rb
new file mode 100644
index 00000000000..6d7453f0de5
--- /dev/null
+++ b/spec/lib/gitlab/ci/pipeline/expression/token_spec.rb
@@ -0,0 +1,45 @@
+require 'spec_helper'
+
+describe Gitlab::Ci::Pipeline::Expression::Token do
+  let(:value) { '$VARIABLE' }
+  let(:lexeme) { Gitlab::Ci::Pipeline::Expression::Lexeme::Variable }
+
+  subject { described_class.new(value, lexeme) }
+
+  describe '#value' do
+    it 'returns raw token value' do
+      expect(subject.value).to eq value
+    end
+  end
+
+  describe '#lexeme' do
+    it 'returns raw token lexeme' do
+      expect(subject.lexeme).to eq lexeme
+    end
+  end
+
+  describe '#build' do
+    it 'delegates to lexeme after adding a value' do
+      expect(lexeme).to receive(:build)
+        .with(value, 'some', 'args')
+
+      subject.build('some', 'args')
+    end
+
+    it 'allows passing only required arguments' do
+      expect(subject.build).to be_an_instance_of(lexeme)
+    end
+  end
+
+  describe '#type' do
+    it 'delegates type query to the lexeme' do
+      expect(subject.type).to eq :value
+    end
+  end
+
+  describe '#to_lexeme' do
+    it 'returns raw lexeme syntax component name' do
+      expect(subject.to_lexeme).to eq 'variable'
+    end
+  end
+end