Add support for SQLite

Rails 8 ships with production-grade SQLite, which means
active_record_doctor should support it, too. This commit adds a test
suite for SQLite3. This required making a few changes:

1. Making the database name used by the test suite depend on the adapter
   as SQLite uses an in-memory database.
2. Dedicated require_* methods for skipping test cases that are relevant
   to the current database under test.
3. Splitting a few test cases into SQLite-specific code and code for
   other databases.

Additionally, short_primary_key is effectively disabled in SQLite.

Author: gregnavis

Rakefile

@@ -24,9 +24,9 @@ RuboCop::RakeTask.new
 require "rake/testtask"
 
 namespace :test do
-  ["postgresql", "mysql2"].each do |adapter|
+  ["postgresql", "mysql2", "sqlite3"].each do |adapter|
     Rake::TestTask.new(adapter) do |t|
-      t.deps = ["set_#{adapter}_env"]
+      t.deps = ["prepare_#{adapter}"]
       t.libs = ["lib", "test"]
       t.ruby_opts = ["-rsetup"]
       t.pattern = "test/**/*_test.rb"
@@ -36,10 +36,12 @@ namespace :test do
       t.warning = false
     end
 
-    task("set_#{adapter}_env") { ENV["DATABASE_ADAPTER"] = adapter }
+    task :"prepare_#{adapter}" do
+      ENV["DATABASE_ADAPTER"] = adapter
+    end
   end
 end
 
-task test: ["test:postgresql", "test:mysql2"]
+task test: ["test:postgresql", "test:mysql2", "test:sqlite3"]
 
 task default: :test

active_record_doctor.gemspec

@@ -28,5 +28,6 @@ Gem::Specification.new do |s|
   s.add_development_dependency "railties", ACTIVE_RECORD_SPEC
   s.add_development_dependency "rake", "~> 13.2.1"
   s.add_development_dependency "rubocop", "~> 1.68.0"
+  s.add_development_dependency "sqlite3", "~> 2.2.0"
   s.add_development_dependency "transient_record", "~> 2.0.0"
 end

lib/active_record_doctor/detectors/short_primary_key_type.rb

@@ -20,6 +20,8 @@ def message(table:, column:)
       end
 
       def detect
+        return if ActiveRecordDoctor::Utils.sqlite?
+
         each_table(except: config(:ignore_tables)) do |table|
           column = primary_key(table)
           next if column.nil?

lib/active_record_doctor/utils.rb

@@ -11,6 +11,10 @@ def mysql?(connection = ActiveRecord::Base.connection)
         connection.adapter_name == "Mysql2"
       end
 
+      def sqlite?(connection = ActiveRecord::Base.connection)
+        connection.adapter_name == "SQLite"
+      end
+
       def expression_indexes_unsupported?(connection = ActiveRecord::Base.connection)
         # Active Record is unable to correctly parse expression indexes for MySQL.
         mysql?(connection) && ActiveRecord::VERSION::STRING < "7.1"

test/active_record_doctor/detectors/extraneous_indexes_test.rb

@@ -12,7 +12,7 @@ def test_index_on_primary_key_is_duplicate
   end
 
   def test_partial_index_on_primary_key
-    skip("MySQL doesn't support partial indexes") if mysql?
+    require_partial_indexes!
 
     Context.create_table(:users) do |t|
       t.boolean :admin
@@ -92,7 +92,7 @@ def test_unique_index_with_fewer_columns
   end
 
   def test_expression_index_not_covered_by_multicolumn_index
-    skip("Expression indexes are not supported") if ActiveRecordDoctor::Utils.expression_indexes_unsupported?
+    require_expression_indexes!
 
     Context.create_table(:users) do |t|
       t.string :first_name
@@ -105,7 +105,7 @@ def test_expression_index_not_covered_by_multicolumn_index
   end
 
   def test_unique_expression_index_not_covered_by_unique_multicolumn_index
-    skip("Expression indexes are not supported") if ActiveRecordDoctor::Utils.expression_indexes_unsupported?
+    require_expression_indexes!
 
     Context.create_table(:users) do |t|
       t.string :first_name
@@ -118,14 +118,16 @@ def test_unique_expression_index_not_covered_by_unique_multicolumn_index
   end
 
   def test_not_covered_by_different_index_type
+    require_additional_index_types!
+
     Context.create_table(:users) do |t|
       t.string :first_name
       t.string :last_name
       t.index [:last_name, :first_name], using: :btree
 
       if mysql?
         t.index :last_name, type: :fulltext
-      else
+      elsif postgresql?
         t.index :last_name, using: :hash
       end
     end
@@ -134,7 +136,7 @@ def test_not_covered_by_different_index_type
   end
 
   def test_not_covered_by_partial_index
-    skip("MySQL doesn't support partial indexes") if mysql?
+    require_partial_indexes!
 
     Context.create_table(:users) do |t|
       t.string :first_name
@@ -148,7 +150,7 @@ def test_not_covered_by_partial_index
   end
 
   def test_not_covered_with_different_opclasses
-    skip("MySQL doesn't support operator classes") if mysql?
+    require_operator_classes!
 
     Context.create_table(:users) do |t|
       t.string :first_name
@@ -161,7 +163,7 @@ def test_not_covered_with_different_opclasses
   end
 
   def test_single_column_covered_by_multi_column_on_materialized_view_is_duplicate
-    skip("Only PostgreSQL supports materialized views") unless postgresql?
+    require_materialized_views!
 
     begin
       Context.create_table(:users) do |t|
@@ -188,8 +190,7 @@ def test_single_column_covered_by_multi_column_on_materialized_view_is_duplicate
   end
 
   def test_include_index_covered_by_other_non_include_index
-    skip("ActiveRecord < 7.1 doesn't support include indexes") if ActiveRecord::VERSION::STRING < "7.1"
-    skip("Only PostgreSQL supports include indexes") unless postgresql?
+    require_non_key_index_columns!
 
     Context.create_table(:users) do |t|
       t.string :first_name
@@ -204,8 +205,7 @@ def test_include_index_covered_by_other_non_include_index
   end
 
   def test_include_index_covered_by_other_include_index
-    skip("ActiveRecord < 7.1 doesn't support include indexes") if ActiveRecord::VERSION::STRING < "7.1"
-    skip("Only PostgreSQL supports include indexes") unless postgresql?
+    require_non_key_index_columns!
 
     Context.create_table(:users) do |t|
       t.string :first_name
@@ -221,8 +221,7 @@ def test_include_index_covered_by_other_include_index
   end
 
   def test_include_index_not_covered_by_other_index
-    skip("ActiveRecord < 7.1 doesn't support include indexes") if ActiveRecord::VERSION::STRING < "7.1"
-    skip("Only PostgreSQL supports include indexes") unless postgresql?
+    require_non_key_index_columns!
 
     Context.create_table(:users) do |t|
       t.string :first_name

test/active_record_doctor/detectors/incorrect_length_validation_test.rb

@@ -26,7 +26,7 @@ def test_validation_and_limit_different_is_error
   end
 
   def test_validation_and_no_limit_is_error
-    skip("MySQL always sets a limit on text columns") if mysql?
+    require_arbitrary_long_text_columns!
 
     Context.create_table(:users) do |t|
       t.string :email
@@ -51,7 +51,7 @@ def test_no_validation_and_limit_is_error
   end
 
   def test_no_validation_and_no_limit_is_ok
-    skip("MySQL always sets a limit on text columns") if mysql?
+    require_arbitrary_long_text_columns!
 
     Context.create_table(:users) do |t|
       t.string :email

test/active_record_doctor/detectors/mismatched_foreign_key_type_test.rb

@@ -2,17 +2,22 @@
 
 class ActiveRecordDoctor::Detectors::MismatchedForeignKeyTypeTest < Minitest::Test
   def test_mismatched_foreign_key_type_is_reported
-    # MySQL does not allow foreign keys to have different type than paired primary keys
-    return if mysql?
+    require_foreign_keys_of_different_type!
 
-    Context.create_table(:companies, id: :bigint)
+    Context.create_table(:companies, id: :smallint)
     Context.create_table(:users) do |t|
       t.references :company, foreign_key: true, type: :integer
     end
 
-    assert_problems(<<~OUTPUT)
-      users.company_id is a foreign key of type integer and references companies.id of type bigint - foreign keys should be of the same type as the referenced column
-    OUTPUT
+    if sqlite?
+      assert_problems(<<~OUTPUT)
+        users.company_id is a foreign key of type INTEGER and references companies.id of type smallint - foreign keys should be of the same type as the referenced column
+      OUTPUT
+    else
+      assert_problems(<<~OUTPUT)
+        users.company_id is a foreign key of type integer and references companies.id of type smallint - foreign keys should be of the same type as the referenced column
+      OUTPUT
+    end
   end
 
   def test_matched_foreign_key_type_is_not_reported
@@ -25,8 +30,7 @@ def test_matched_foreign_key_type_is_not_reported
   end
 
   def test_mismatched_foreign_key_with_non_primary_key_type_is_reported
-    # MySQL does not allow foreign keys to have different type than paired primary keys
-    return if mysql?
+    require_foreign_keys_of_different_type!
 
     Context.create_table(:companies, id: :bigint) do |t|
       t.string :code
@@ -37,9 +41,15 @@ def test_mismatched_foreign_key_with_non_primary_key_type_is_reported
       t.foreign_key :companies, table: :companies, column: :code, primary_key: :code
     end
 
-    assert_problems(<<~OUTPUT)
-      users.code is a foreign key of type text and references companies.code of type character varying - foreign keys should be of the same type as the referenced column
-    OUTPUT
+    if sqlite?
+      assert_problems(<<~OUTPUT)
+        users.code is a foreign key of type TEXT and references companies.code of type varchar - foreign keys should be of the same type as the referenced column
+      OUTPUT
+    else
+      assert_problems(<<~OUTPUT)
+        users.code is a foreign key of type text and references companies.code of type character varying - foreign keys should be of the same type as the referenced column
+      OUTPUT
+    end
   end
 
   def test_matched_foreign_key_with_non_primary_key_type_is_not_reported
@@ -59,8 +69,7 @@ def test_matched_foreign_key_with_non_primary_key_type_is_not_reported
   end
 
   def test_config_ignore_tables
-    # MySQL does not allow foreign keys to have different type than paired primary keys
-    return if mysql?
+    require_foreign_keys_of_different_type!
 
     Context.create_table(:companies, id: :bigint)
     Context.create_table(:users) do |t|
@@ -78,8 +87,7 @@ def test_config_ignore_tables
   end
 
   def test_global_ignore_tables
-    # MySQL does not allow foreign keys to have different type than paired primary keys
-    return if mysql?
+    require_foreign_keys_of_different_type!
 
     Context.create_table(:companies, id: :bigint)
     Context.create_table(:users) do |t|
@@ -96,8 +104,7 @@ def test_global_ignore_tables
   end
 
   def test_config_ignore_columns
-    # MySQL does not allow foreign keys to have different type than paired primary keys
-    return if mysql?
+    require_foreign_keys_of_different_type!
 
     Context.create_table(:companies, id: :bigint)
     Context.create_table(:users) do |t|

test/active_record_doctor/detectors/missing_non_null_constraint_test.rb

@@ -40,7 +40,7 @@ def test_optional_columns_with_required_polymorphic_association_are_disallowed
   end
 
   def test_optional_foreign_keys_with_required_with_if_association_are_disallowed
-    skip("ActiveRecord < 7.1 doesn't support optimized association presence validation") if ActiveRecord::VERSION::STRING < "7.1"
+    require_optimized_association_presence_validations!
 
     begin
       previous = ActiveRecord.belongs_to_required_validates_foreign_key
@@ -228,37 +228,25 @@ def test_custom_sti_column_is_ignored
   end
 
   def test_not_null_check_constraint
-    skip unless postgresql?
-
     Context.create_table(:users) do |t|
-      t.string :email
+      if !sqlite?
+        t.string :email
+      end
     end.define_model do
       validates :email, presence: true
     end
 
-    ActiveRecord::Base.connection.execute(<<-SQL)
-      ALTER TABLE users ADD CONSTRAINT email_not_null CHECK (email IS NOT NULL)
-    SQL
-
-    refute_problems
-  end
-
-  def test_not_null_check_constraint_not_valid
-    skip unless postgresql?
-
-    Context.create_table(:users) do |t|
-      t.string :email
-    end.define_model do
-      validates :email, presence: true
+    if sqlite?
+      ActiveRecord::Base.connection.execute(<<-SQL)
+        ALTER TABLE users ADD COLUMN email VARCHAR CONSTRAINT email_not_null CHECK (email IS NOT NULL)
+      SQL
+    else
+      ActiveRecord::Base.connection.execute(<<-SQL)
+        ALTER TABLE users ADD CONSTRAINT email_not_null CHECK (email IS NOT NULL)
+      SQL
     end
 
-    ActiveRecord::Base.connection.execute(<<-SQL)
-      ALTER TABLE users ADD CONSTRAINT email_not_null CHECK (email IS NOT NULL) NOT VALID
-    SQL
-
-    assert_problems(<<~OUTPUT)
-      add `NOT NULL` to users.email - models validates its presence but it's not non-NULL in the database
-    OUTPUT
+    refute_problems
   end
 
   def test_config_ignore_tables

test/active_record_doctor/detectors/missing_presence_validation_test.rb

@@ -146,35 +146,27 @@ def test_models_with_non_existent_tables_are_skipped
   end
 
   def test_not_null_check_constraint
-    skip unless postgresql?
-
     Context.create_table(:users) do |t|
-      t.string :name
+      if !sqlite?
+        t.string :name
+      end
     end.define_model
 
-    ActiveRecord::Base.connection.execute(<<-SQL)
-      ALTER TABLE users ADD CONSTRAINT name_not_null CHECK (name IS NOT NULL)
-    SQL
+    if sqlite?
+      ActiveRecord::Base.connection.execute(<<-SQL)
+        ALTER TABLE users ADD COLUMN name VARCHAR CONSTRAINT name_not_null CHECK (name IS NOT NULL)
+      SQL
+    else
+      ActiveRecord::Base.connection.execute(<<-SQL)
+        ALTER TABLE users ADD CONSTRAINT name_not_null CHECK (name IS NOT NULL)
+      SQL
+    end
 
     assert_problems(<<~OUTPUT)
       add a `presence` validator to Context::User.name - it's NOT NULL but lacks a validator
     OUTPUT
   end
 
-  def test_not_null_check_constraint_not_valid
-    skip unless postgresql?
-
-    Context.create_table(:users) do |t|
-      t.string :name
-    end.define_model
-
-    ActiveRecord::Base.connection.execute(<<-SQL)
-      ALTER TABLE users ADD CONSTRAINT name_not_null CHECK (name IS NOT NULL) NOT VALID
-    SQL
-
-    refute_problems
-  end
-
   def test_abstract_class
     Context.define_model(:ApplicationRecord) do
       self.abstract_class = true