Adjust the no-association-lines logic

On very small clusters, the node count heuristic is impractical and
leads to confusion. By additionally requiring 10+ sibling allocs, the
lines will be shown more often.

ui/app/components/topo-viz.js

@@ -220,8 +220,8 @@ export default class TopoViz extends Component {
         });
       }
 
-      // Only show the lines if the selected allocations are sparse (low count relative to the client count).
-      if (newAllocations.length < this.args.nodes.length * 0.75) {
+      // Only show the lines if the selected allocations are sparse (low count relative to the client count or low count generally).
+      if (newAllocations.length < 10 || newAllocations.length < this.args.nodes.length * 0.75) {
         this.computedActiveEdges();
       } else {
         this.activeEdges = [];

ui/tests/integration/components/topo-viz-test.js

@@ -157,8 +157,17 @@ module('Integration | Component | TopoViz', function(hooks) {
     this.setProperties({
       nodes: [node('dc1', 'node0', 1000, 500), node('dc1', 'node1', 1000, 500)],
       allocations: [
+        // There need to be at least 10 sibling allocations to trigger this behavior
         alloc('node0', 'job1', 'group', 100, 100),
         alloc('node0', 'job1', 'group', 100, 100),
+        alloc('node0', 'job1', 'group', 100, 100),
+        alloc('node0', 'job1', 'group', 100, 100),
+        alloc('node0', 'job1', 'group', 100, 100),
+        alloc('node0', 'job1', 'group', 100, 100),
+        alloc('node1', 'job1', 'group', 100, 100),
+        alloc('node1', 'job1', 'group', 100, 100),
+        alloc('node1', 'job1', 'group', 100, 100),
+        alloc('node1', 'job1', 'group', 100, 100),
         alloc('node1', 'job1', 'group', 100, 100),
         alloc('node1', 'job1', 'group', 100, 100),
         alloc('node0', 'job1', 'groupTwo', 100, 100),