`WhereClause#predicates` does not need to be public

The only place it was accessed was in tests. Many of them have another
way that they can test their behavior, that doesn't involve reaching
into internals as far as they did. `AssociationScopeTest` is testing a
situation where the where clause would have one bind param per
predicate, so it can just ignore the predicates entirely. The where
chain test was primarly duplicating the logic tested on `WhereClause`
directly, so I instead just make sure it calls the appropriate method
which is fully tested in isolation.

2 files changed, 27 insertions, 102 deletions

diff --git a/activerecord/test/cases/relation/where_chain_test.rb b/activerecord/test/cases/relation/where_chain_test.rb
index 00c9a001c0..27bbd80f79 100644
--- a/activerecord/test/cases/relation/where_chain_test.rb
+++ b/activerecord/test/cases/relation/where_chain_test.rb
@@ -11,22 +11,11 @@ module ActiveRecord
       @name = 'title'
     end
 
-    def test_not_eq
+    def test_not_inverts_where_clause
       relation = Post.where.not(title: 'hello')
+      expected_where_clause = Post.where(title: 'hello').where_clause.invert
 
-      assert_equal 1, relation.where_clause.predicates.length
-
-      value = relation.where_clause.predicates.first
-      bind  = relation.where_clause.binds.first
-
-      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::NotEqual
-      assert_equal 'hello', bind.last
-    end
-
-    def test_not_null
-      expected = Post.arel_table[@name].not_eq(nil)
-      relation = Post.where.not(title: nil)
-      assert_equal([expected], relation.where_clause.predicates)
+      assert_equal expected_where_clause, relation.where_clause
     end
 
     def test_not_with_nil
@@ -35,146 +24,81 @@ module ActiveRecord
       end
     end
 
-    def test_not_in
-      expected = Post.arel_table[@name].not_in(%w[hello goodbye])
-      relation = Post.where.not(title: %w[hello goodbye])
-      assert_equal([expected], relation.where_clause.predicates)
-    end
-
     def test_association_not_eq
-      expected = Comment.arel_table[@name].not_eq(Arel::Nodes::BindParam.new)
+      expected = Arel::Nodes::Grouping.new(Comment.arel_table[@name].not_eq(Arel::Nodes::BindParam.new))
       relation = Post.joins(:comments).where.not(comments: {title: 'hello'})
-      assert_equal(expected.to_sql, relation.where_clause.predicates.first.to_sql)
+      assert_equal(expected.to_sql, relation.where_clause.ast.to_sql)
     end
 
     def test_not_eq_with_preceding_where
       relation = Post.where(title: 'hello').where.not(title: 'world')
+      expected_where_clause =
+        Post.where(title: 'hello').where_clause +
+        Post.where(title: 'world').where_clause.invert
 
-      value = relation.where_clause.predicates.first
-      bind  = relation.where_clause.binds.first
-      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::Equality
-      assert_equal 'hello', bind.last
-
-      value = relation.where_clause.predicates.last
-      bind  = relation.where_clause.binds.last
-      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::NotEqual
-      assert_equal 'world', bind.last
+      assert_equal expected_where_clause, relation.where_clause
     end
 
     def test_not_eq_with_succeeding_where
       relation = Post.where.not(title: 'hello').where(title: 'world')
+      expected_where_clause =
+        Post.where(title: 'hello').where_clause.invert +
+        Post.where(title: 'world').where_clause
 
-      value = relation.where_clause.predicates.first
-      bind  = relation.where_clause.binds.first
-      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::NotEqual
-      assert_equal 'hello', bind.last
-
-      value = relation.where_clause.predicates.last
-      bind  = relation.where_clause.binds.last
-      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::Equality
-      assert_equal 'world', bind.last
-    end
-
-    def test_not_eq_with_string_parameter
-      expected = Arel::Nodes::Not.new("title = 'hello'")
-      relation = Post.where.not("title = 'hello'")
-      assert_equal([expected], relation.where_clause.predicates)
-    end
-
-    def test_not_eq_with_array_parameter
-      expected = Arel::Nodes::Not.new("title = 'hello'")
-      relation = Post.where.not(['title = ?', 'hello'])
-      assert_equal([expected], relation.where_clause.predicates)
+      assert_equal expected_where_clause, relation.where_clause
     end
 
     def test_chaining_multiple
       relation = Post.where.not(author_id: [1, 2]).where.not(title: 'ruby on rails')
+      expected_where_clause =
+        Post.where(author_id: [1, 2]).where_clause.invert +
+        Post.where(title: 'ruby on rails').where_clause.invert
 
-      expected = Post.arel_table['author_id'].not_in([1, 2])
-      assert_equal(expected, relation.where_clause.predicates[0])
-
-      value = relation.where_clause.predicates[1]
-      bind  = relation.where_clause.binds.first
-
-      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::NotEqual
-      assert_equal 'ruby on rails', bind.last
+      assert_equal expected_where_clause, relation.where_clause
     end
 
     def test_rewhere_with_one_condition
       relation = Post.where(title: 'hello').where(title: 'world').rewhere(title: 'alone')
+      expected = Post.where(title: 'alone')
 
-      assert_equal 1, relation.where_clause.predicates.size
-      value = relation.where_clause.predicates.first
-      bind = relation.where_clause.binds.first
-      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::Equality
-      assert_equal 'alone', bind.last
+      assert_equal expected.where_clause, relation.where_clause
     end
 
     def test_rewhere_with_multiple_overwriting_conditions
       relation = Post.where(title: 'hello').where(body: 'world').rewhere(title: 'alone', body: 'again')
+      expected = Post.where(title: 'alone', body: 'again')
 
-      assert_equal 2, relation.where_clause.predicates.size
-
-      value = relation.where_clause.predicates.first
-      bind = relation.where_clause.binds.first
-      assert_bound_ast value, Post.arel_table['title'], Arel::Nodes::Equality
-      assert_equal 'alone', bind.last
-
-      value = relation.where_clause.predicates[1]
-      bind = relation.where_clause.binds[1]
-      assert_bound_ast value, Post.arel_table['body'], Arel::Nodes::Equality
-      assert_equal 'again', bind.last
-    end
-
-    def assert_bound_ast value, table, type
-      assert_equal table, value.left
-      assert_kind_of type, value
-      assert_kind_of Arel::Nodes::BindParam, value.right
+      assert_equal expected.where_clause, relation.where_clause
     end
 
     def test_rewhere_with_one_overwriting_condition_and_one_unrelated
       relation = Post.where(title: 'hello').where(body: 'world').rewhere(title: 'alone')
+      expected = Post.where(body: 'world', title: 'alone')
 
-      assert_equal 2, relation.where_clause.predicates.size
-
-      value = relation.where_clause.predicates.first
-      bind  = relation.where_clause.binds.first
-
-      assert_bound_ast value, Post.arel_table['body'], Arel::Nodes::Equality
-      assert_equal 'world', bind.last
-
-      value = relation.where_clause.predicates.second
-      bind  = relation.where_clause.binds.second
-
-      assert_bound_ast value, Post.arel_table['title'], Arel::Nodes::Equality
-      assert_equal 'alone', bind.last
+      assert_equal expected.where_clause, relation.where_clause
     end
 
     def test_rewhere_with_range
       relation = Post.where(comments_count: 1..3).rewhere(comments_count: 3..5)
 
-      assert_equal 1, relation.where_clause.predicates.size
       assert_equal Post.where(comments_count: 3..5), relation
     end
 
     def test_rewhere_with_infinite_upper_bound_range
       relation = Post.where(comments_count: 1..Float::INFINITY).rewhere(comments_count: 3..5)
 
-      assert_equal 1, relation.where_clause.predicates.size
       assert_equal Post.where(comments_count: 3..5), relation
     end
 
     def test_rewhere_with_infinite_lower_bound_range
       relation = Post.where(comments_count: -Float::INFINITY..1).rewhere(comments_count: 3..5)
 
-      assert_equal 1, relation.where_clause.predicates.size
       assert_equal Post.where(comments_count: 3..5), relation
     end
 
     def test_rewhere_with_infinite_range
       relation = Post.where(comments_count: -Float::INFINITY..Float::INFINITY).rewhere(comments_count: 3..5)
 
-      assert_equal 1, relation.where_clause.predicates.size
       assert_equal Post.where(comments_count: 3..5), relation
     end
   end
diff --git a/activerecord/test/cases/relation/where_clause_test.rb b/activerecord/test/cases/relation/where_clause_test.rb
index 511d595f71..f3644154b6 100644
--- a/activerecord/test/cases/relation/where_clause_test.rb
+++ b/activerecord/test/cases/relation/where_clause_test.rb
@@ -112,11 +112,12 @@ class ActiveRecord::Relation
     end
 
     test "ast groups its predicates with AND" do
-      where_clause = WhereClause.new([
+      predicates = [
         table["id"].in([1, 2, 3]),
         table["name"].eq(bind_param),
-      ], [])
-      expected = Arel::Nodes::And.new(where_clause.predicates)
+      ]
+      where_clause = WhereClause.new(predicates, [])
+      expected = Arel::Nodes::And.new(predicates)
 
       assert_equal expected, where_clause.ast
     end