treewide: replace error comparisons and assertions with errors.Is

Change-Id: Id2424eb155f2c6842c72c5fafd124d428ef901f2
Reviewed-on: https://review.monogon.dev/c/monogon/+/2994
Tested-by: Jenkins CI
Reviewed-by: Serge Bazanski <serge@monogon.tech>
diff --git a/metropolis/pkg/event/memory/memory_test.go b/metropolis/pkg/event/memory/memory_test.go
index 98a1501..80ac575 100644
--- a/metropolis/pkg/event/memory/memory_test.go
+++ b/metropolis/pkg/event/memory/memory_test.go
@@ -18,6 +18,7 @@
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"sync"
 	"sync/atomic"
@@ -294,7 +295,7 @@
 
 	// Cancel the context, and expect that context error to propagate to the .Get().
 	ctxC()
-	if want, got := ctx.Err(), <-errs; want != got {
+	if want, got := ctx.Err(), <-errs; !errors.Is(got, want) {
 		t.Fatalf("Get should've returned %v, got %v", want, got)
 	}
 
@@ -308,7 +309,7 @@
 
 	// Unblock the .Get now.
 	p.Set(1)
-	if want, got := error(nil), <-errs; want != got {
+	if want, got := error(nil), <-errs; !errors.Is(got, want) {
 		t.Fatalf("Get should've returned %v, got %v", want, got)
 	}
 }