Add unit tests

Author: schneems

spec/unit/visitor_spec.rb

@@ -0,0 +1,121 @@
+# frozen_string_literal: true
+
+require_relative "../spec_helper"
+
+module SyntaxSuggest
+  RSpec.describe Visitor do
+    def visit(source)
+      ast, _tokens = Prism.parse_lex(source).value
+      visitor = Visitor.new
+      visitor.visit(ast)
+      visitor
+    end
+
+    describe "#consecutive_lines" do
+      it "detects dot-leading multi-line chains" do
+        visitor = visit(<<~RUBY)
+          User
+            .where(name: "Earlopain")
+            .first
+        RUBY
+
+        expect(visitor.consecutive_lines).to eq([1, 2])
+      end
+
+      it "detects dot-trailing multi-line chains" do
+        visitor = visit(<<~RUBY)
+          User.
+            where(name: "Earlopain").
+            first
+        RUBY
+
+        expect(visitor.consecutive_lines).to eq([1, 2])
+      end
+
+      it "handles chains separated by comments" do
+        visitor = visit(<<~RUBY)
+          User.
+            # comment
+            where(name: "Earlopain").
+            # another comment
+            first
+        RUBY
+
+        # The AST sees through comments — every line except
+        # the last is consecutive regardless of interleaved comments.
+        expect(visitor.consecutive_lines).to eq([1, 2, 3, 4])
+      end
+
+      it "returns empty for single-line calls" do
+        visitor = visit(<<~RUBY)
+          User.where(name: "Earlopain").first
+        RUBY
+
+        expect(visitor.consecutive_lines).to eq([])
+      end
+
+      it "returns empty when there is no method chain" do
+        visitor = visit(<<~RUBY)
+          puts "hello"
+          puts "world"
+        RUBY
+
+        expect(visitor.consecutive_lines).to eq([])
+      end
+
+      it "handles deeply nested chains" do
+        visitor = visit(<<~RUBY)
+          User
+            .where(name: "Earlopain")
+            .order(:created_at)
+            .limit(10)
+            .first
+        RUBY
+
+        expect(visitor.consecutive_lines).to eq([1, 2, 3, 4])
+      end
+    end
+
+    describe "#endless_def_keyword_locs" do
+      it "records the def location for endless methods" do
+        visitor = visit(<<~RUBY)
+          def square(x) = x * x
+        RUBY
+
+        expect(visitor.endless_def_keyword_locs.length).to eq(1)
+        expect(visitor.endless_def_keyword_locs.first.start_line).to eq(1)
+      end
+
+      it "does not record regular method definitions" do
+        visitor = visit(<<~RUBY)
+          def square(x)
+            x * x
+          end
+        RUBY
+
+        expect(visitor.endless_def_keyword_locs).to be_empty
+      end
+
+      it "records multiple endless methods" do
+        visitor = visit(<<~RUBY)
+          def square(x) = x * x
+          def double(x) = x * 2
+        RUBY
+
+        expect(visitor.endless_def_keyword_locs.length).to eq(2)
+      end
+
+      it "distinguishes endless from regular in the same source" do
+        visitor = visit(<<~RUBY)
+          def square(x) = x * x
+          def cube(x)
+            x * x * x
+          end
+        RUBY
+
+        expect(visitor.endless_def_keyword_locs.length).to eq(1)
+        expect(visitor.endless_def_keyword_locs.first.start_line).to eq(1)
+      end
+    end
+  end
+end