Add test for storing state just under the size limit of the Consul backend

Storing a state just a bit smaller than the limit of the KV API fails
because we are using the Transaction API which has an overhead.

internal/backend/remote-state/consul/client_test.go

@@ -136,11 +136,6 @@ func TestConsul_largeState(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		// md5 := md5.Sum(payload)
-		// if !bytes.Equal(md5[:], remote.MD5) {
-		// 	t.Fatal("the md5 sums do not match")
-		// }
-
 		if !bytes.Equal(payload, remote.Data) {
 			t.Fatal("the data do not match")
 		}
@@ -161,6 +156,19 @@ func TestConsul_largeState(t *testing.T) {
 		},
 	)
 
+	// This payload is just short enough to be stored but will be bigger when
+	// going through the Transaction API as it will be base64 encoded
+	testPayload(
+		t,
+		map[string]string{
+			"foo": strings.Repeat("a", 524288-10),
+		},
+		[]string{
+			"tf-unit/test-large-state",
+			"tf-unit/test-large-state/tfstate.4f407ace136a86521fd0d366972fe5c7/0",
+		},
+	)
+
 	// We try to replace the payload with a small one, the old chunks should be removed
 	testPayload(
 		t,