mcp23017: use new tester package

Also change the `tester` package slightly to use an exposed `Registers`
array rather adding yet another accessor method to retrieve a register
value. This seems to me more transparent and "obvious" - we aren't trying
to hide the fact that there's just a simple memory store there.
Also unexport the `assertRegisterRange` method which was never intended
to be part of the public API.

adt7410/adt7410_test.go

@@ -18,13 +18,13 @@ func TestWhoAmI(t *testing.T) {
 	c := qt.New(t)
 	bus := tester.NewI2CBus(c)
 	fake := tester.NewI2CDevice(c, Address)
-	fake.SetupRegisters(defaultRegisters())
+	copy(fake.Registers[:], defaultRegisters())
 	bus.AddDevice(fake)
 
 	dev := New(bus)
 	c.Assert(dev.Connected(), qt.Equals, true)
 
-	fake.SetupRegister(RegID, 0x99)
+	fake.Registers[RegID] = 0x99
 	c.Assert(dev.Connected(), qt.Equals, false)
 }
 

lis2mdl/lis2mdl_test.go

@@ -18,13 +18,13 @@ func TestWhoAmI(t *testing.T) {
 	c := qt.New(t)
 	bus := tester.NewI2CBus(c)
 	fake := tester.NewI2CDevice(c, ADDRESS)
-	fake.SetupRegisters(defaultRegisters())
+	copy(fake.Registers[:], defaultRegisters())
 	bus.AddDevice(fake)
 
 	dev := New(bus)
 	c.Assert(dev.Connected(), qt.Equals, true)
 
-	fake.SetupRegister(WHO_AM_I, 0x99)
+	fake.Registers[WHO_AM_I] = 0x99
 	c.Assert(dev.Connected(), qt.Equals, false)
 }
 

mcp23017/device_test.go

@@ -5,12 +5,14 @@ import (
 	"testing"
 
 	qt "github.com/frankban/quicktest"
+
+	"tinygo.org/x/drivers/tester"
 )
 
 func TestGetPins(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev := bus.addDevice(0x20)
+	bus := tester.NewI2CBus(c)
+	fdev := newDevice(bus, 0x20)
 	fdev.Registers[rGPIO] = 0b10101100
 	fdev.Registers[rGPIO|portB] = 0b01010011
 	dev, err := NewI2C(bus, 0x20)
@@ -22,8 +24,8 @@ func TestGetPins(t *testing.T) {
 
 func TestSetPins(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev := bus.addDevice(0x20)
+	bus := tester.NewI2CBus(c)
+	fdev := newDevice(bus, 0x20)
 	fdev.Registers[rGPIO] = 0b00001111
 	fdev.Registers[rGPIO|portB] = 0b11110000
 	dev, err := NewI2C(bus, 0x20)
@@ -52,8 +54,8 @@ func TestSetPins(t *testing.T) {
 
 func TestTogglePins(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev := bus.addDevice(0x20)
+	bus := tester.NewI2CBus(c)
+	fdev := newDevice(bus, 0x20)
 	fdev.Registers[rGPIO] = 0b00001111
 	fdev.Registers[rGPIO|portB] = 0b11110000
 	dev, err := NewI2C(bus, 0x20)
@@ -71,8 +73,8 @@ func TestTogglePins(t *testing.T) {
 
 func TestSetGetModes(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev := bus.addDevice(0x20)
+	bus := tester.NewI2CBus(c)
+	fdev := newDevice(bus, 0x20)
 	dev, err := NewI2C(bus, 0x20)
 	c.Assert(err, qt.IsNil)
 	// Calling SetModes with less items in than there are
@@ -102,8 +104,8 @@ func TestSetGetModes(t *testing.T) {
 
 func TestPinSetGet(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev := bus.addDevice(0x20)
+	bus := tester.NewI2CBus(c)
+	fdev := newDevice(bus, 0x20)
 	dev, err := NewI2C(bus, 0x20)
 	c.Assert(err, qt.IsNil)
 	pin := dev.Pin(1)
@@ -129,8 +131,8 @@ func TestPinSetGet(t *testing.T) {
 
 func TestPinToggle(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev := bus.addDevice(0x20)
+	bus := tester.NewI2CBus(c)
+	fdev := newDevice(bus, 0x20)
 	dev, err := NewI2C(bus, 0x20)
 	c.Assert(err, qt.IsNil)
 	pin := dev.Pin(1)
@@ -147,8 +149,8 @@ func TestPinToggle(t *testing.T) {
 
 func TestPinMode(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev := bus.addDevice(0x20)
+	bus := tester.NewI2CBus(c)
+	fdev := newDevice(bus, 0x20)
 	dev, err := NewI2C(bus, 0x20)
 	c.Assert(err, qt.IsNil)
 	pin := dev.Pin(1)
@@ -201,10 +203,18 @@ func TestPins(t *testing.T) {
 
 func TestInitWithError(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev := bus.addDevice(0x20)
+	bus := tester.NewI2CBus(c)
+	fdev := newDevice(bus, 0x20)
 	fdev.Err = fmt.Errorf("some error")
 	dev, err := NewI2C(bus, 0x20)
 	c.Assert(err, qt.ErrorMatches, `cannot initialize mcp23017 device at 0x20: some error`)
 	c.Assert(dev, qt.IsNil)
 }
+
+func newDevice(bus *tester.I2CBus, addr uint8) *tester.I2CDevice {
+	fdev := bus.NewDevice(addr)
+	// IODIRA and IODIRB are all ones by default.
+	fdev.Registers[rIODIR] = 0xff
+	fdev.Registers[rIODIR|portB] = 0xff
+	return fdev
+}

mcp23017/fakedev_test.go

@@ -1,97 +0,0 @@
-package mcp23017
-
-import (
-	qt "github.com/frankban/quicktest"
-)
-
-// fakeBus implements the I2C interface in memory for testing.
-type fakeBus struct {
-	c    *qt.C
-	devs []*fakeDev
-}
-
-// newBus returns a fakeBus instance that uses c to flag errors
-// if they happen. After creating a fakeBus instance, add devices
-// to it with addDevice before using the interface.
-func newBus(c *qt.C) *fakeBus {
-	return &fakeBus{
-		c: c,
-	}
-}
-
-// fakeDev represents a device on the bus.
-type fakeDev struct {
-	c    *qt.C
-	addr uint8
-	// Registers holds the device registers. It can be inspected
-	// or changed as desired for testing.
-	Registers [registerCount]uint8
-	// If Err is non-nil, it will be returned as the error from the
-	// I2C methods.
-	Err error
-}
-
-// addDevice adds a new device at the given address.
-func (bus *fakeBus) addDevice(addr uint8) *fakeDev {
-	dev := &fakeDev{
-		c:    bus.c,
-		addr: addr,
-		Registers: [registerCount]uint8{
-			// IODIRA and IODIRB are all ones by default.
-			rIODIR:         0xff,
-			rIODIR | portB: 0xff,
-		},
-	}
-	bus.devs = append(bus.devs, dev)
-	return dev
-}
-
-// ReadRegister implements I2C.ReadRegister.
-func (bus *fakeBus) ReadRegister(addr uint8, r uint8, buf []byte) error {
-	return bus.findDev(addr).readRegister(r, buf)
-}
-
-// WriteRegister implements I2C.WriteRegister.
-func (bus *fakeBus) WriteRegister(addr uint8, r uint8, buf []byte) error {
-	return bus.findDev(addr).writeRegister(r, buf)
-}
-
-func (d *fakeDev) readRegister(r uint8, buf []byte) error {
-	if d.Err != nil {
-		return d.Err
-	}
-	d.assertRegisterRange(r, buf)
-	copy(buf, d.Registers[r:])
-	return nil
-}
-
-func (d *fakeDev) writeRegister(r uint8, buf []byte) error {
-	if d.Err != nil {
-		return d.Err
-	}
-	d.assertRegisterRange(r, buf)
-	copy(d.Registers[r:], buf)
-	return nil
-}
-
-// assertRegisterRange asserts that reading or writing the given
-// register and subsequent registers is in range of the available registers.
-func (d *fakeDev) assertRegisterRange(r uint8, buf []byte) {
-	if int(r) >= len(d.Registers) {
-		d.c.Fatalf("register read/write [%#x, %#x] start out of range", r, int(r)+len(buf))
-	}
-	if int(r)+len(buf) > len(d.Registers) {
-		d.c.Fatalf("register read/write [%#x, %#x] end out of range", r, int(r)+len(buf))
-	}
-}
-
-// findDev returns the device with the given address.
-func (bus *fakeBus) findDev(addr uint8) *fakeDev {
-	for _, dev := range bus.devs {
-		if dev.addr == addr {
-			return dev
-		}
-	}
-	bus.c.Fatalf("invalid device addr %#x passed to i2c bus", addr)
-	panic("unreachable")
-}

mcp23017/multidevice_test.go

@@ -4,13 +4,15 @@ import (
 	"testing"
 
 	qt "github.com/frankban/quicktest"
+
+	"tinygo.org/x/drivers/tester"
 )
 
 func TestDevicesGetPins(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev0 := bus.addDevice(0x20)
-	fdev1 := bus.addDevice(0x21)
+	bus := tester.NewI2CBus(c)
+	fdev0 := newDevice(bus, 0x20)
+	fdev1 := newDevice(bus, 0x21)
 	fdev0.Registers[rGPIO] = 0b10101100
 	fdev0.Registers[rGPIO|portB] = 0b01010011
 	fdev1.Registers[rGPIO] = 0b10101101
@@ -31,9 +33,9 @@ func TestDevicesGetPins(t *testing.T) {
 
 func TestDevicesSetPinsAllOff(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev0 := bus.addDevice(0x20)
-	fdev1 := bus.addDevice(0x21)
+	bus := tester.NewI2CBus(c)
+	fdev0 := newDevice(bus, 0x20)
+	fdev1 := newDevice(bus, 0x21)
 	fdev0.Registers[rGPIO] = 0b10101100
 	fdev0.Registers[rGPIO|portB] = 0b01010011
 	fdev1.Registers[rGPIO] = 0b10101101
@@ -51,9 +53,9 @@ func TestDevicesSetPinsAllOff(t *testing.T) {
 
 func TestDevicesSetPinsAllOn(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev0 := bus.addDevice(0x20)
-	fdev1 := bus.addDevice(0x21)
+	bus := tester.NewI2CBus(c)
+	fdev0 := newDevice(bus, 0x20)
+	fdev1 := newDevice(bus, 0x21)
 	fdev0.Registers[rGPIO] = 0b10101100
 	fdev0.Registers[rGPIO|portB] = 0b01010011
 	fdev1.Registers[rGPIO] = 0b10101101
@@ -71,9 +73,9 @@ func TestDevicesSetPinsAllOn(t *testing.T) {
 
 func TestDevicesSetPinsMask(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev0 := bus.addDevice(0x20)
-	fdev1 := bus.addDevice(0x21)
+	bus := tester.NewI2CBus(c)
+	fdev0 := newDevice(bus, 0x20)
+	fdev1 := newDevice(bus, 0x21)
 	fdev0.Registers[rGPIO] = 0b10101100
 	fdev0.Registers[rGPIO|portB] = 0b01010011
 	fdev1.Registers[rGPIO] = 0b10101101
@@ -104,9 +106,9 @@ func TestDevicesSetPinsMask(t *testing.T) {
 
 func TestDevicesTogglePins(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	bus.addDevice(0x20)
-	bus.addDevice(0x21)
+	bus := tester.NewI2CBus(c)
+	newDevice(bus, 0x20)
+	newDevice(bus, 0x21)
 	devs, err := NewI2CDevices(bus, 0x20, 0x21)
 	c.Assert(err, qt.IsNil)
 
@@ -124,9 +126,9 @@ func TestDevicesTogglePins(t *testing.T) {
 
 func TestDevicesSetGetModes(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	fdev0 := bus.addDevice(0x20)
-	fdev1 := bus.addDevice(0x21)
+	bus := tester.NewI2CBus(c)
+	fdev0 := newDevice(bus, 0x20)
+	fdev1 := newDevice(bus, 0x21)
 	devs, err := NewI2CDevices(bus, 0x20, 0x21)
 	c.Assert(err, qt.IsNil)
 	// Sanity check that IODIR registers start off all ones.
@@ -154,9 +156,9 @@ func TestDevicesSetGetModes(t *testing.T) {
 
 func TestDevicesPin(t *testing.T) {
 	c := qt.New(t)
-	bus := newBus(c)
-	bus.addDevice(0x20)
-	fdev1 := bus.addDevice(0x21)
+	bus := tester.NewI2CBus(c)
+	newDevice(bus, 0x20)
+	fdev1 := newDevice(bus, 0x21)
 	devs, err := NewI2CDevices(bus, 0x20, 0x21)
 	c.Assert(err, qt.IsNil)
 	pin := devs.Pin(16)

tester/device.go

@@ -10,7 +10,7 @@ type I2CDevice struct {
 	addr uint8
 	// Registers holds the device registers. It can be inspected
 	// or changed as desired for testing.
-	registers [MaxRegisters]uint8
+	Registers [MaxRegisters]uint8
 	// If Err is non-nil, it will be returned as the error from the
 	// I2C methods.
 	Err error
@@ -29,35 +29,13 @@ func (d *I2CDevice) Addr() uint8 {
 	return d.addr
 }
 
-// SetupRegisters sets all of the Device registers.
-// It is intended to be used when setting up a fake device
-// for testing expected vs. actual values.
-func (d *I2CDevice) SetupRegisters(regs []uint8) {
-	if len(regs) > MaxRegisters {
-		panic("exceeded maximum number of registers for fake device")
-	}
-	for k, v := range regs {
-		d.registers[k] = v
-	}
-}
-
-// SetupRegister sets one of the Device registers.
-// It is intended to be used when setting up a fake device
-// for testing expected vs. actual values.
-func (d *I2CDevice) SetupRegister(r, v uint8) {
-	if r > MaxRegisters {
-		panic("exceeded maximum number of registers for fake device")
-	}
-	d.registers[r] = v
-}
-
 // ReadRegister implements I2C.ReadRegister.
 func (d *I2CDevice) ReadRegister(r uint8, buf []byte) error {
 	if d.Err != nil {
 		return d.Err
 	}
-	d.AssertRegisterRange(r, buf)
-	copy(buf, d.registers[r:])
+	d.assertRegisterRange(r, buf)
+	copy(buf, d.Registers[r:])
 	return nil
 }
 
@@ -66,18 +44,18 @@ func (d *I2CDevice) WriteRegister(r uint8, buf []byte) error {
 	if d.Err != nil {
 		return d.Err
 	}
-	d.AssertRegisterRange(r, buf)
-	copy(d.registers[r:], buf)
+	d.assertRegisterRange(r, buf)
+	copy(d.Registers[r:], buf)
 	return nil
 }
 
-// AssertRegisterRange asserts that reading or writing the given
+// assertRegisterRange asserts that reading or writing the given
 // register and subsequent registers is in range of the available registers.
-func (d *I2CDevice) AssertRegisterRange(r uint8, buf []byte) {
-	if int(r) >= len(d.registers) {
+func (d *I2CDevice) assertRegisterRange(r uint8, buf []byte) {
+	if int(r) >= len(d.Registers) {
 		d.c.Fatalf("register read/write [%#x, %#x] start out of range", r, int(r)+len(buf))
 	}
-	if int(r)+len(buf) > len(d.registers) {
+	if int(r)+len(buf) > len(d.Registers) {
 		d.c.Fatalf("register read/write [%#x, %#x] end out of range", r, int(r)+len(buf))
 	}
 }

tester/i2c.go

@@ -1,5 +1,7 @@
 package tester
 
+import "fmt"
+
 // I2CBus implements the I2C interface in memory for testing.
 type I2CBus struct {
 	c       Failer
@@ -16,10 +18,24 @@ func NewI2CBus(c Failer) *I2CBus {
 }
 
 // AddDevice adds a new mock device to the mock I2C bus.
+// It panics if a device with the same address is added more than once.
 func (bus *I2CBus) AddDevice(d *I2CDevice) {
+	for _, dev := range bus.devices {
+		if dev.Addr() == d.addr {
+			panic(fmt.Errorf("device already added at address %#x", d))
+		}
+	}
 	bus.devices = append(bus.devices, d)
 }
 
+// NewDevice creates a new device with the given address
+// and adds it to the mock I2C bus.
+func (bus *I2CBus) NewDevice(addr uint8) *I2CDevice {
+	dev := NewI2CDevice(bus.c, addr)
+	bus.AddDevice(dev)
+	return dev
+}
+
 // ReadRegister implements I2C.ReadRegister.
 func (bus *I2CBus) ReadRegister(addr uint8, r uint8, buf []byte) error {
 	return bus.FindDevice(addr).ReadRegister(r, buf)