Merge branch '153-plot-grirwm-crashes-with-a-single-node' into 'dev'

Resolve "plot.GRirwm crashes with a single node"

Closes #153

See merge request !96

R/plot.GRiwrm.R

@@ -49,13 +49,17 @@ plot.GRiwrm <- function(x,
   x <- sortGRiwrm4plot(x)
   nodes <- unlist(sapply(unique(x$donor), plotGriwrmCluster, x = x, with_donors = with_donors))
   g2 <- x[!is.na(x$down),]
-  links <- paste(
-    sprintf("id_%1$s", g2$id),
-    "-->|",
-    round(g2$length, digits = 0),
-    "km|",
-    sprintf("id_%1$s", g2$down)
-  )
+  if (nrow(g2) > 0) {
+    links <- paste(
+      sprintf("id_%1$s", g2$id),
+      "-->|",
+      round(g2$length, digits = 0),
+      "km|",
+      sprintf("id_%1$s", g2$down)
+    )
+  } else {
+    links <- ""
+  }
   x$nodeclass <- sapply(x$id, getNodeClass, griwrm = x)
   node_class <- lapply(unique(x$nodeclass), function(nc) {
     x$id[x$nodeclass == nc]

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)
+  expect_false(grepl("-->", mmd, fixed = TRUE))
+})