Add session and cookie concepts.

- Add tests for callbacks.
- Refactor callbacks into a keyed map.

callbacks_test.go

@@ -0,0 +1,38 @@
+package authboss
+
+import "testing"
+
+func TestCallbacks(t *testing.T) {
+	afterCalled := false
+	beforeCalled := false
+	c := NewCallbacks()
+
+	c.Before(EventRegister, func(ctx *Context) error {
+		beforeCalled = true
+		return nil
+	})
+	c.After(EventRegister, func(ctx *Context) {
+		afterCalled = true
+	})
+
+	if beforeCalled || afterCalled {
+		t.Error("Neither should be called.")
+	}
+
+	err := c.FireBefore(EventRegister, NewContext())
+	if err != nil {
+		t.Error("Unexpected error:", err)
+	}
+
+	if !beforeCalled {
+		t.Error("Expected before to have been called.")
+	}
+	if afterCalled {
+		t.Error("Expected after not to be called.")
+	}
+
+	c.FireAfter(EventRegister, NewContext())
+	if !afterCalled {
+		t.Error("Expected after to be called.")
+	}
+}