Work through TODO fixes

internal/app/child_input_test.go

@@ -0,0 +1,29 @@
+package app
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestInputWritePiecesOnlySplitAgentEnters(t *testing.T) {
+	in := []byte("alpha\nbeta\rgamma")
+	for _, kind := range []ChildKind{KindTerminal, KindCommand} {
+		t.Run(string(kind), func(t *testing.T) {
+			got := inputWritePieces(kind, in)
+			if len(got) != 1 || !bytes.Equal(got[0], in) {
+				t.Fatalf("inputWritePieces(%s) = %#v, want one original chunk", kind, got)
+			}
+		})
+	}
+
+	got := inputWritePieces(KindAgent, in)
+	if len(got) != 5 {
+		t.Fatalf("agent pieces len = %d, want 5 (%#v)", len(got), got)
+	}
+	want := [][]byte{[]byte("alpha"), []byte("\n"), []byte("beta"), []byte("\r"), []byte("gamma")}
+	for i := range want {
+		if !bytes.Equal(got[i], want[i]) {
+			t.Fatalf("agent piece %d = %q, want %q", i, got[i], want[i])
+		}
+	}
+}