Add operator / value types in pipeline expressions

lib/gitlab/ci/pipeline/expression/lexeme/equals.rb

@@ -3,9 +3,8 @@ module Gitlab
     module Pipeline
       module Expression
         module Lexeme
-          class Equals < Lexeme::Base
+          class Equals < Lexeme::Operator
             PATTERN = /==/.freeze
-            TYPE = :operator
 
             def initialize(left, right)
               @left = left

lib/gitlab/ci/pipeline/expression/lexeme/null.rb

@@ -3,9 +3,8 @@ module Gitlab
     module Pipeline
       module Expression
         module Lexeme
-          class Null < Lexeme::Base
+          class Null < Lexeme::Value
             PATTERN = /null/.freeze
-            TYPE = :value
 
             def initialize(value = nil)
               @value = value

lib/gitlab/ci/pipeline/expression/lexeme/operator.rb

+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        module Lexeme
+          class Operator < Lexeme::Base
+            def self.type
+              :operator
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/ci/pipeline/expression/lexeme/string.rb

@@ -3,9 +3,8 @@ module Gitlab
     module Pipeline
       module Expression
         module Lexeme
-          class String < Lexeme::Base
+          class String < Lexeme::Value
             PATTERN = /"(?<string>.+?)"/.freeze
-            TYPE = :value
 
             def initialize(value)
               @value = value

lib/gitlab/ci/pipeline/expression/lexeme/value.rb

+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        module Lexeme
+          class Value < Lexeme::Base
+            def self.type
+              :value
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/ci/pipeline/expression/lexeme/variable.rb

@@ -3,9 +3,8 @@ module Gitlab
     module Pipeline
       module Expression
         module Lexeme
-          class Variable < Lexeme::Base
+          class Variable < Lexeme::Value
             PATTERN = /\$(?<name>\w+)/.freeze
-            TYPE = :value
 
             def initialize(name)
               @name = name

lib/gitlab/ci/pipeline/expression/lexer.rb

@@ -10,7 +10,7 @@ module Gitlab
           ].freeze
 
           MAX_CYCLES = 5
-          SyntaxError = Class.new(StandardError)
+          SyntaxError = Class.new(Statement::StatementError)
 
           def initialize(statement)
             @scanner = StringScanner.new(statement)

lib/gitlab/ci/pipeline/expression/parser.rb

@@ -22,7 +22,7 @@ module Gitlab
               end
             end
           rescue StopIteration
-            @nodes.last || Expression::Lexeme::Null.new
+            @nodes.last || Lexeme::Null.new
           end
 
           def self.seed(statement)

spec/lib/gitlab/ci/pipeline/expression/statement_spec.rb

@@ -23,13 +23,22 @@ describe Gitlab::Ci::Pipeline::Expression::Statement do
     end
 
     context 'when expression grammar is incorrect' do
-      let(:text) { '$VAR "text"' }
-
-      it 'raises an error' do
-        expect { subject.parse_tree }
+      table = [
+        '$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