seesaw: device support and tests

seesaw/mocki2c_test.go

@@ -0,0 +1,48 @@
+package seesaw
+
+import (
+	"encoding/hex"
+	"fmt"
+	"testing"
+)
+
+type I2CHandleFunc func(t *testing.T, w, r []byte) error
+
+// mocki2c implements the drivers.I2C interface and matches a list
+// of handlers against actual invocations. Useful to test command/reply style I2C devices.
+type mocki2c struct {
+	addr     uint16
+	handlers []I2CHandleFunc
+	t        *testing.T
+}
+
+func (m *mocki2c) Tx(addr uint16, w, r []byte) error {
+	assertEquals(m.t, addr, m.addr)
+	if len(m.handlers) == 0 {
+		ws := hex.EncodeToString(w)
+		rs := hex.EncodeToString(r)
+		panic(fmt.Sprintf("no handlers for: addr='%02x' w='%s' r='%s'", byte(addr), ws, rs))
+	}
+	h := m.handlers[0]
+	m.handlers = m.handlers[1:]
+	return h(m.t, w, r)
+}
+
+func newMockDev(t *testing.T, addr uint16, handlers ...I2CHandleFunc) *mocki2c {
+	return &mocki2c{
+		addr:     addr,
+		handlers: handlers,
+		t:        t,
+	}
+}
+
+func when(expectedWrite, returningRead []byte, returningError error) I2CHandleFunc {
+	return func(t *testing.T, w, r []byte) error {
+		assertEquals(t, w, expectedWrite)
+		assertEquals(t, len(r), len(returningRead))
+		if r != nil {
+			copy(r, returningRead)
+		}
+		return returningError
+	}
+}