1 files changed, 105 insertions, 0 deletions
diff --git a/devtools/client/memory/test/xpcshell/test_tree-map-02.js b/devtools/client/memory/test/xpcshell/test_tree-map-02.js
new file mode 100644
index 0000000000..528c59dcfa
--- /dev/null
+++ b/devtools/client/memory/test/xpcshell/test_tree-map-02.js
@@ -0,0 +1,105 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const {
+  drawText,
+} = require("resource://devtools/client/memory/components/tree-map/draw.js");
+
+add_task(async function () {
+  // Mock out the Canvas2dContext
+  const ctx = {
+    fillText: (...args) => fillTextValues.push(args),
+    measureText: text => {
+      const width = text ? text.length * 10 : 0;
+      return { width };
+    },
+  };
+  const node = {
+    x: 20,
+    y: 30,
+    dx: 500,
+    dy: 70,
+    name: "Example Node",
+    totalBytes: 1200,
+    totalCount: 100,
+  };
+  const ratio = 0;
+  const borderWidth = () => 1;
+  const dragZoom = {
+    offsetX: 0,
+    offsetY: 0,
+    zoom: 0,
+  };
+  let fillTextValues = [];
+  const padding = [10, 10];
+
+  drawText(ctx, node, borderWidth, ratio, dragZoom, padding);
+  deepEqual(
+    fillTextValues[0],
+    ["Example Node", 11.5, 21.5],
+    "Fills in the full node name"
+  );
+  deepEqual(
+    fillTextValues[1],
+    ["1KiB 100 count", 141.5, 21.5],
+    "Includes the full byte and count information"
+  );
+
+  fillTextValues = [];
+  node.dx = 250;
+  drawText(ctx, node, borderWidth, ratio, dragZoom, padding);
+
+  deepEqual(
+    fillTextValues[0],
+    ["Example Node", 11.5, 21.5],
+    "Fills in the full node name"
+  );
+  deepEqual(
+    fillTextValues[1],
+    undefined,
+    "Drops off the byte and count information if not enough room"
+  );
+
+  fillTextValues = [];
+  node.dx = 100;
+  drawText(ctx, node, borderWidth, ratio, dragZoom, padding);
+
+  deepEqual(
+    fillTextValues[0],
+    ["Exampl...", 11.5, 21.5],
+    "Cuts the name with ellipsis"
+  );
+  deepEqual(
+    fillTextValues[1],
+    undefined,
+    "Drops off the byte and count information if not enough room"
+  );
+
+  fillTextValues = [];
+  node.dx = 40;
+  drawText(ctx, node, borderWidth, ratio, dragZoom, padding);
+
+  deepEqual(
+    fillTextValues[0],
+    ["...", 11.5, 21.5],
+    "Shows only ellipsis when smaller"
+  );
+  deepEqual(
+    fillTextValues[1],
+    undefined,
+    "Drops off the byte and count information if not enough room"
+  );
+
+  fillTextValues = [];
+  node.dx = 20;
+  drawText(ctx, node, borderWidth, ratio, dragZoom, padding);
+
+  deepEqual(fillTextValues[0], undefined, "Draw nothing when not enough room");
+  deepEqual(
+    fillTextValues[1],
+    undefined,
+    "Drops off the byte and count information if not enough room"
+  );
+});