Import spec examples from ruby/syntax_suggest

Merged: https://github.com/ruby/ruby/pull/6287

spec/syntax_suggest/unit/explain_syntax_spec.rb

@@ -0,0 +1,255 @@
+# frozen_string_literal: true
+
+require_relative "../spec_helper"
+
+module SyntaxSuggest
+  RSpec.describe "ExplainSyntax" do
+    it "handles shorthand syntaxes with non-bracket characters" do
+      source = <<~EOM
+        %Q* lol
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq([])
+      expect(explain.errors.join).to include("unterminated string")
+    end
+
+    it "handles %w[]" do
+      source = <<~EOM
+        node.is_a?(Op) && %w[| ||].include?(node.value) &&
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq([])
+    end
+
+    it "doesn't falsely identify strings or symbols as critical chars" do
+      source = <<~EOM
+        a = ['(', '{', '[', '|']
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq([])
+
+      source = <<~EOM
+        a = [:'(', :'{', :'[', :'|']
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq([])
+    end
+
+    it "finds missing |" do
+      source = <<~EOM
+        Foo.call do |
+        end
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq(["|"])
+      expect(explain.errors).to eq([explain.why("|")])
+    end
+
+    it "finds missing {" do
+      source = <<~EOM
+        class Cat
+          lol = {
+        end
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq(["}"])
+      expect(explain.errors).to eq([explain.why("}")])
+    end
+
+    it "finds missing }" do
+      source = <<~EOM
+        def foo
+          lol = "foo" => :bar }
+        end
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq(["{"])
+      expect(explain.errors).to eq([explain.why("{")])
+    end
+
+    it "finds missing [" do
+      source = <<~EOM
+        class Cat
+          lol = [
+        end
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq(["]"])
+      expect(explain.errors).to eq([explain.why("]")])
+    end
+
+    it "finds missing ]" do
+      source = <<~EOM
+        def foo
+          lol = ]
+        end
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq(["["])
+      expect(explain.errors).to eq([explain.why("[")])
+    end
+
+    it "finds missing (" do
+      source = "def initialize; ); end"
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq(["("])
+      expect(explain.errors).to eq([explain.why("(")])
+    end
+
+    it "finds missing )" do
+      source = "def initialize; (; end"
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq([")"])
+      expect(explain.errors).to eq([explain.why(")")])
+    end
+
+    it "finds missing keyword" do
+      source = <<~EOM
+        class Cat
+          end
+        end
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq(["keyword"])
+      expect(explain.errors).to eq([explain.why("keyword")])
+    end
+
+    it "finds missing end" do
+      source = <<~EOM
+        class Cat
+          def meow
+        end
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq(["end"])
+      expect(explain.errors).to eq([explain.why("end")])
+    end
+
+    it "falls back to ripper on unknown errors" do
+      source = <<~EOM
+        class Cat
+          def meow
+            1 *
+          end
+        end
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq([])
+      expect(explain.errors).to eq(RipperErrors.new(source).call.errors)
+    end
+
+    it "handles an unexpected rescue" do
+      source = <<~EOM
+        def foo
+          if bar
+            "baz"
+          else
+            "foo"
+        rescue FooBar
+          nil
+        end
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq(["end"])
+    end
+
+    # String embeds are `"#{foo} <-- here`
+    #
+    # We need to count a `#{` as a `{`
+    # otherwise it will report that we are
+    # missing a curly when we are using valid
+    # string embed syntax
+    it "is not confused by valid string embed" do
+      source = <<~'EOM'
+        foo = "#{hello}"
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+      expect(explain.missing).to eq([])
+    end
+
+    # Missing string embed beginnings are not a
+    # syntax error. i.e. `"foo}"` or `"{foo}` or "#foo}"
+    # would just be strings with extra characters.
+    #
+    # However missing the end curly will trigger
+    # an error: i.e. `"#{foo`
+    #
+    # String embed beginning is a `#{` rather than
+    # a `{`, make sure we handle that case and
+    # report the correct missing `}` diagnosis
+    it "finds missing string embed end" do
+      source = <<~'EOM'
+        "#{foo
+      EOM
+
+      explain = ExplainSyntax.new(
+        code_lines: CodeLine.from_source(source)
+      ).call
+
+      expect(explain.missing).to eq(["}"])
+    end
+  end
+end