test: run model with provided input and check output

tea_test.go

@@ -0,0 +1,39 @@
+package tea
+
+import (
+	"bytes"
+	"testing"
+)
+
+type testModel struct{}
+
+func (m testModel) Init() Cmd {
+	return nil
+}
+
+func (m testModel) Update(msg Msg) (Model, Cmd) {
+	switch msg.(type) {
+	case KeyMsg:
+		return m, Quit
+	}
+	return m, nil
+}
+
+func (m testModel) View() string {
+	return "success\n"
+}
+
+func TestTeaModel(t *testing.T) {
+	var buf bytes.Buffer
+	var in bytes.Buffer
+	in.Write([]byte("q"))
+
+	p := NewProgram(testModel{}, WithInput(&in), WithOutput(&buf))
+	if err := p.Start(); err != nil {
+		t.Fatal(err)
+	}
+
+	if buf.Len() == 0 {
+		t.Fatal("no output")
+	}
+}