Add io_provider specs

spec/dummy_driver.cr

@@ -9,6 +9,7 @@ class DummyDriver < DB::Driver
   class DummyConnection < DB::Connection
     def initialize(context)
       super(context)
+      context.io_provider.try &.build_io
       @connected = true
       @@connections ||= [] of DummyConnection
       @@connections.not_nil! << self

spec/io_provider_spec.cr

@@ -0,0 +1,54 @@
+require "./spec_helper"
+require "log/spec"
+
+class DummyIOProvider < DB::IOProvider
+  @setup_called = false
+  @teardown_called = false
+
+  def setup : Void
+    raise "setup called twice" if @setup_called
+    @setup_called = true
+    DB::Log.debug &.emit("DummyIOProvider#setup")
+  end
+
+  def teardown : Void
+    raise "teardown called twice" if @teardown_called
+    @teardown_called = true
+    DB::Log.debug &.emit("DummyIOProvider#teardown")
+  end
+
+  def build_io : IO
+    DB::Log.debug &.emit("DummyIOProvider#build_io")
+    return IO::Memory.new
+  end
+end
+
+describe DB::IOProvider do
+  it "setup/teardown are called for pool connection" do
+    Log.capture(DB::Log.source) do |logs|
+      DB.open "dummy://host", io_provider: DummyIOProvider.new do |db|
+        cnn1 = db.checkout
+        cnn2 = db.checkout
+
+        db.release(cnn1)
+        db.release(cnn2)
+      end
+
+      logs.check(:debug, /DummyIOProvider#setup/i)
+      logs.check(:debug, /DummyIOProvider#build_io/i)
+      logs.check(:debug, /DummyIOProvider#build_io/i)
+      logs.check(:debug, /DummyIOProvider#teardown/i)
+    end
+  end
+
+  it "setup/teardown are called for single connection" do
+    Log.capture(DB::Log.source) do |logs|
+      DB.connect "dummy://host", io_provider: DummyIOProvider.new do |cnn|
+      end
+
+      logs.check(:debug, /DummyIOProvider#setup/i)
+      logs.check(:debug, /DummyIOProvider#build_io/i)
+      logs.check(:debug, /DummyIOProvider#teardown/i)
+    end
+  end
+end