backend: remove parameter validation tests

These parameter validations have been factored out into
SemaphoreBackend.

internal/backend/dryrun/dry_backend_test.go

@@ -40,11 +40,9 @@ func TestDry(t *testing.T) {
 		{d, "delete", "", "", ""},
 		{d, "stat", "a", "", "not found"},
 		{d, "list", "", "", ""},
-		{d, "save", "", "", "invalid"},
 		{m, "save", "a", "baz", ""},  // save a directly to the mem backend
 		{d, "save", "b", "foob", ""}, // b is not saved
 		{d, "save", "b", "xxx", ""},  // no error as b is not saved
-		{d, "stat", "", "", "invalid"},
 		{d, "stat", "a", "a 3", ""},
 		{d, "load", "a", "baz", ""},
 		{d, "load", "b", "", "not found"},

internal/backend/test/tests.go

@@ -124,17 +124,7 @@ func (s *Suite) TestLoad(t *testing.T) {
 	b := s.open(t)
 	defer s.close(t, b)
 
-	noop := func(rd io.Reader) error {
-		return nil
-	}
-
-	err := b.Load(context.TODO(), restic.Handle{}, 0, 0, noop)
-	if err == nil {
-		t.Fatalf("Load() did not return an error for invalid handle")
-	}
-	test.Assert(t, !b.IsNotExist(err), "IsNotExist() should not accept an invalid handle error: %v", err)
-
-	err = testLoad(b, restic.Handle{Type: restic.PackFile, Name: "foobar"}, 0, 0)
+	err := testLoad(b, restic.Handle{Type: restic.PackFile, Name: "foobar"}, 0, 0)
 	if err == nil {
 		t.Fatalf("Load() did not return an error for non-existing blob")
 	}
@@ -153,11 +143,6 @@ func (s *Suite) TestLoad(t *testing.T) {
 
 	t.Logf("saved %d bytes as %v", length, handle)
 
-	err = b.Load(context.TODO(), handle, 100, -1, noop)
-	if err == nil {
-		t.Fatalf("Load() returned no error for negative offset!")
-	}
-
 	err = b.Load(context.TODO(), handle, 0, 0, func(rd io.Reader) error {
 		_, err := io.Copy(io.Discard, rd)
 		if err != nil {