test(plot.GRiwrm): add test for a single node network

Refs #153

tests/testthat/test-plot.GRiwrm.R

@@ -11,7 +11,7 @@ test_that("Diverted ungauged nodes have correct color", {
   expect_true(any(grepl("id_54029 UpstreamUngaugedDiversion", strsplit(mmd, "\n\n")[[1]])))
 })
 
-test_that("Unguaged nodes and donors are in a box!", {
+test_that("Ungauged nodes and donors are in a box!", {
   nds <- loadSevernNodes()
   nds$donor <- as.character(NA)
   nds$model[nds$id %in% c("54001", "54032", "54029")] <- "Ungauged"
@@ -23,3 +23,10 @@ test_that("Unguaged nodes and donors are in a box!", {
   s <- plot(g, display = FALSE)
   expect_equal(strsplit(s, "\n")[[1]][c(5,13)], c("subgraph donor_54095 [54095]", "end"))
 })
+
+test_that("Single node plot does not crash", {
+  sgl_node <- loadSevernNodes()[1,]
+  g <- CreateGRiwrm(sgl_node)
+  mmd <- plot(g, display = FALSE)
+  expectfalse(grepl("-->", mmd, fixed = TRUE))
+})