Add Expectf(format string, v ...any)

actually.go

@@ -2,6 +2,7 @@
 package actually
 
 import (
+	"fmt"
 	"testing"
 )
 
@@ -59,3 +60,24 @@ func (a *testingA) Expect(e any) *testingA {
 
 	return a
 }
+
+// Expectf sets the formatted string value you expect to be the same as the one you got.
+// Expectf creates *testingA and returns it.
+func Expectf(format string, e ...any) *testingA {
+	return &testingA{
+		expect:    fmt.Sprintf(format, e...),
+		setExpect: true,
+	}
+}
+
+// Expectf sets the formatted string value you expect to be the same as the one you got.
+func (a *testingA) Expectf(format string, e ...any) *testingA {
+	if a.setExpect {
+		panic(panicReason_CalledExpectTwice)
+	}
+
+	a.expect = fmt.Sprintf(format, e...)
+	a.setExpect = true
+
+	return a
+}

actually_test.go

@@ -84,3 +84,12 @@ func TestDuplicateCall(t *testing.T) {
 		t.Error("panic wouldn't happen")
 	}
 }
+
+func TestExpectf(t *testing.T) {
+	Expectf("%s def", "abc").Got("abc def").Same(t)
+}
+
+func TestActuallyExpectf(t *testing.T) {
+	a := &testingA{}
+	a.Expectf("%s def", "abc").Got("abc def").Same(t)
+}