Test that following causes voting power to refresh.

rs/nns/governance/tests/governance.rs

@@ -1737,6 +1737,18 @@ async fn test_all_follow_proposer() {
         driver.get_fake_ledger(),
         driver.get_fake_cmc(),
     );
+
+    // Later, we'll inspect the same field again to verify that voting power
+    // refresh actually took place. This is just to make sure that the later
+    // value is different from this earlier one.
+    assert_eq!(
+        gov.with_neuron(&NeuronId { id: 5 }, |neuron| {
+            neuron.voting_power_refreshed_timestamp_seconds()
+        })
+        .unwrap(),
+        DEFAULT_VOTING_POWER_REFRESHED_TIMESTAMP_SECONDS,
+    );
+
     // Add following for 5 and 6 for 1.
     gov.manage_neuron(
         // Must match neuron 5's serialized_id.
@@ -1754,6 +1766,22 @@ async fn test_all_follow_proposer() {
     .unwrap()
     .panic_if_error("Manage neuron failed");
 
+    // Assert that neuron 5's voting power was refreshed. More concretely,
+    // verifying that neuron 5's voting_power_refreshed_timestamp_seconds
+    // changed from before. (Earlier, we saw that this field had a different
+    // value, to wit, DEFAULT_VOTING_POWER_REFRESHED_TIMESTAMP_SECONDS)
+    assert_ne!(
+        DEFAULT_TEST_START_TIMESTAMP_SECONDS,
+        DEFAULT_VOTING_POWER_REFRESHED_TIMESTAMP_SECONDS,
+    );
+    assert_eq!(
+        gov.with_neuron(&NeuronId { id: 5 }, |neuron| {
+            neuron.voting_power_refreshed_timestamp_seconds()
+        })
+        .unwrap(),
+        DEFAULT_TEST_START_TIMESTAMP_SECONDS,
+    );
+
     gov.manage_neuron(
         // Must match neuron 6's serialized_id.
         &principal(6),