diff --git a/spec/cars.cr b/spec/cars.cr
new file mode 100644
index 0000000..f65c52c
--- /dev/null
+++ b/spec/cars.cr
@@ -0,0 +1,78 @@
+# This file contains all the necessary code to perform tests based on the following Car database.
+
+require "json"
+require "../src/dodb.cr"
+require "./spec-database.cr"
+
+class Car
+	include JSON::Serializable
+
+	property name     : String        # unique to each instance (1-1 relations)
+	property color    : String        # a simple attribute (1-n relations)
+	property keywords : Array(String) # tags about a car, example: "shiny" (n-n relations)
+
+	def_clone
+
+	def initialize(@name, @color, @keywords)
+	end
+	class_getter cars = [
+		Car.new("Corvet",    "red",    [ "shiny", "impressive", "fast", "elegant" ]),
+		Car.new("SUV",       "red",    [ "solid", "impressive" ]),
+		Car.new("Mustang",   "red",    [ "shiny", "impressive", "elegant" ]),
+		Car.new("Bullet-GT", "red",    [ "shiny", "impressive", "fast", "elegant" ]),
+		Car.new("GTI",       "blue",   [ "average" ]),
+		Car.new("Deudeuch",  "violet", [ "dirty", "slow", "only French will understand" ])
+	]
+
+	# Equality is true if every property is identical.
+	def ==(other)
+		@name == other.name && @color == other.color && @keywords == other.keywords
+	end
+end
+
+def ram_indexes(storage : DODB::Storage)
+	n = storage.new_RAM_index "name", &.name
+	c = storage.new_RAM_partition "color", &.color
+	k = storage.new_RAM_tags "keyword", &.keywords
+	return n, c, k
+end
+
+def cached_indexes(storage : DODB::Storage)
+	n = storage.new_index "name", &.name
+	c = storage.new_partition "color", &.color
+	k = storage.new_tags "keyword", &.keywords
+	return n, c, k
+end
+
+def uncached_indexes(storage : DODB::Storage)
+	n = storage.new_uncached_index "name", &.name
+	c = storage.new_uncached_partition "color", &.color
+	k = storage.new_uncached_tags "keyword", &.keywords
+	return n, c, k
+end
+
+def add_cars(storage : DODB::Storage, nb_iterations : Int32, from = 0)
+	i = from
+	car1 = Car.new "Corvet", "red", [ "shiny", "impressive", "fast", "elegant" ]
+	car2 = Car.new "Bullet-GT", "blue", [ "shiny", "fast", "expensive" ]
+	car3 = Car.new "Deudeuche", "beige", [ "curvy", "sublime" ]
+	car4 = Car.new "Ford-5", "red", [ "unknown" ]
+	car5 = Car.new "C-MAX", "gray", [ "spacious", "affordable" ]
+
+	while i < nb_iterations
+		car1.name = "Corvet-#{i}"
+		car2.name = "Bullet-GT-#{i}"
+		car3.name = "Deudeuche-#{i}"
+		car4.name = "Ford-5-#{i}"
+		car5.name = "C-MAX-#{i}"
+
+		storage << car1
+		storage << car2
+		storage << car3
+		storage << car4
+		storage << car5
+		i += 1
+		#STDOUT.write "\radding value #{i}".to_slice
+	end
+	#puts ""
+end
diff --git a/spec/spec-database.cr b/spec/spec-database.cr
new file mode 100644
index 0000000..6a78f8e
--- /dev/null
+++ b/spec/spec-database.cr
@@ -0,0 +1,50 @@
+class DODB::SpecDataBase(V) < DODB::DataBase(V)
+	property storage_dir : String
+	def initialize(storage_ext = "", remove_previous_data = true)
+		@storage_dir = "test-spec-storage#{storage_ext}"
+
+		if remove_previous_data
+			::FileUtils.rm_rf storage_dir
+		end
+
+		super storage_dir
+	end
+
+	def rm_storage_dir
+		::FileUtils.rm_rf @storage_dir
+	end
+end
+
+class DODB::CachedSpecDataBase(V) < DODB::CachedDataBase(V)
+	property storage_dir : String
+	def initialize(storage_ext = "", remove_previous_data = true)
+		@storage_dir = "test-spec-storage-cached#{storage_ext}"
+
+		if remove_previous_data
+			::FileUtils.rm_rf storage_dir
+		end
+
+		super storage_dir
+	end
+
+	def rm_storage_dir
+		::FileUtils.rm_rf @storage_dir
+	end
+end
+
+class DODB::RAMOnlySpecDataBase(V) < DODB::RAMOnlyDataBase(V)
+	property storage_dir : String
+	def initialize(storage_ext = "", remove_previous_data = true)
+		@storage_dir = "test-spec-storage-ram#{storage_ext}"
+
+		if remove_previous_data
+			::FileUtils.rm_rf storage_dir
+		end
+
+		super storage_dir
+	end
+
+	def rm_storage_dir
+		::FileUtils.rm_rf @storage_dir
+	end
+end
diff --git a/spec/test-data.cr b/spec/test-data.cr
index 42da67e..2df42ed 100644
--- a/spec/test-data.cr
+++ b/spec/test-data.cr
@@ -85,24 +85,3 @@ class PrimitiveShip
 		@@asakaze
 	]
 end
-
-class Car
-	include JSON::Serializable
-
-	property name     : String        # unique to each instance (1-1 relations)
-	property color    : String        # a simple attribute (1-n relations)
-	property keywords : Array(String) # tags about a car, example: "shiny" (n-n relations)
-
-	def_clone
-
-	def initialize(@name, @color, @keywords)
-	end
-	class_getter cars = [
-		Car.new("Corvet",    "red",    [ "shiny", "impressive", "fast", "elegant" ]),
-		Car.new("SUV",       "red",    [ "solid", "impressive" ]),
-		Car.new("Mustang",   "red",    [ "shiny", "impressive", "elegant" ]),
-		Car.new("Bullet-GT", "red",    [ "shiny", "impressive", "fast", "elegant" ]),
-		Car.new("GTI",       "blue",   [ "average" ]),
-		Car.new("Deudeuch",  "violet", [ "dirty", "slow", "only French will understand" ])
-	]
-end
diff --git a/spec/test.cr b/spec/test.cr
index cb26ab6..25f265e 100644
--- a/spec/test.cr
+++ b/spec/test.cr
@@ -2,28 +2,17 @@ require "spec"
 require "file_utils"
 
 require "../src/dodb.cr"
+require "./spec-database.cr"
 require "./test-data.cr"
 
 def fork_process(&)
 	Process.new Crystal::System::Process.fork { yield }
 end
 
-class DODB::SpecDataBase < DODB::DataBase(Ship)
-	def initialize(storage_ext = "", remove_previous_data = true)
-		storage_dir = "test-storage#{storage_ext}"
-
-		if remove_previous_data
-			::FileUtils.rm_rf storage_dir
-		end
-
-		super storage_dir
-	end
-end
-
 describe "DODB::DataBase" do
 	describe "basics" do
 		it "store and get data" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			Ship.all_ships.each do |ship|
 				db << ship
@@ -33,7 +22,7 @@ describe "DODB::DataBase" do
 		end
 
 		it "rewrite already stored data" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 			ship = Ship.all_ships[0]
 
 			key = db << ship
@@ -45,7 +34,7 @@ describe "DODB::DataBase" do
 		end
 
 		it "properly remove data" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			Ship.all_ships.each do |ship|
 				db << ship
@@ -66,19 +55,19 @@ describe "DODB::DataBase" do
 		end
 
 		it "preserves data on reopening" do
-			db1 = DODB::SpecDataBase.new
+			db1 = DODB::SpecDataBase(Ship).new
 			db1 << Ship.kisaragi
 
 			db1.to_a.size.should eq(1)
 
-			db2 = DODB::SpecDataBase.new remove_previous_data: false
+			db2 = DODB::SpecDataBase(Ship).new remove_previous_data: false
 			db2 << Ship.mutsuki
 
 			db1.to_a.size.should eq(2)
 		end
 
 		it "iterates in normal and reversed order" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			Ship.all_ships.each do |ship|
 				db << ship
@@ -98,7 +87,7 @@ describe "DODB::DataBase" do
 		end
 
 		it "respects the provided offsets if any" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			Ship.all_ships.each do |ship|
 				db << ship
@@ -116,7 +105,7 @@ describe "DODB::DataBase" do
 
 	describe "indices" do
 		it "do basic indexing" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			db_ships_by_name = db.new_index "name", &.name
 
@@ -130,7 +119,7 @@ describe "DODB::DataBase" do
 		end
 
 		it "raise on index overload" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			db_ships_by_name = db.new_index "name", &.name
 
@@ -144,7 +133,7 @@ describe "DODB::DataBase" do
 		end
 
 		it "properly deindex" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			db_ships_by_name = db.new_index "name", &.name
 
@@ -162,7 +151,7 @@ describe "DODB::DataBase" do
 		end
 
 		it "properly reindex" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			db_ships_by_name = db.new_index "name", &.name
 
@@ -180,7 +169,7 @@ describe "DODB::DataBase" do
 		end
 
 		it "properly updates" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			db_ships_by_name = db.new_index "name", &.name
 
@@ -202,7 +191,7 @@ describe "DODB::DataBase" do
 
 	describe "partitions" do
 		it "do basic partitioning" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			db_ships_by_class = db.new_partition "class", &.klass
 
@@ -230,7 +219,7 @@ describe "DODB::DataBase" do
 		end
 
 		it "removes select elements from partitions" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			db_ships_by_class = db.new_partition "class", &.klass
 
@@ -250,7 +239,7 @@ describe "DODB::DataBase" do
 
 	describe "tags" do
 		it "do basic tagging" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			db_ships_by_tags = db.new_tags "tags", &.tags
 
@@ -271,7 +260,7 @@ describe "DODB::DataBase" do
 		end
 
 		it "properly removes tags" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			db_ships_by_tags = db.new_tags "tags", &.tags
 
@@ -295,7 +284,7 @@ describe "DODB::DataBase" do
 		end
 
 		it "gets items that have multiple tags" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			db_ships_by_tags = db.new_tags "tags", &.tags
 
@@ -316,7 +305,7 @@ describe "DODB::DataBase" do
 
 	describe "atomic operations" do
 		it "safe_get and safe_get?" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			db_ships_by_name = db.new_index "name", &.name
 
@@ -338,7 +327,7 @@ describe "DODB::DataBase" do
 
 	describe "tools" do
 		it "rebuilds indexes" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			db_ships_by_name  = db.new_index     "name", &.name
 			db_ships_by_class = db.new_partition "class", &.klass
@@ -370,7 +359,7 @@ describe "DODB::DataBase" do
 			# At this point, the “old” DB is filled. Now we need to convert
 			# to the new DB.
 
-			new_db = DODB::SpecDataBase.new "-migration-target"
+			new_db = DODB::SpecDataBase(Ship).new "-migration-target"
 
 			new_ships_by_name  = new_db.new_index     "name", &.name
 			new_ships_by_class = new_db.new_partition "class", &.klass
@@ -407,7 +396,7 @@ describe "DODB::DataBase" do
 		entries_per_fork = 100
 
 		it "works for pushing values" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 
 			processes = [] of Process
 
@@ -427,7 +416,7 @@ describe "DODB::DataBase" do
 		end
 
 		it "works for updating values" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 			db_entries_by_name = db.new_index "name", &.name
 
 			# First pass, creating data.
@@ -465,7 +454,7 @@ describe "DODB::DataBase" do
 		end
 
 		it "does parallel-safe updates" do
-			db = DODB::SpecDataBase.new
+			db = DODB::SpecDataBase(Ship).new
 			db_entries_by_name = db.new_index "name", &.name
 
 			# We’ll be storing an integer in the "klass" field, and incrementing