chore: add more tests

Author: hacdias

cid_test.go

@@ -777,14 +777,49 @@ func TestLoggable(t *testing.T) {
 	}
 }
 
-func TestErrInvalidCid(t *testing.T) {
-	_, err := Decode("not-a-cid")
-	if err == nil {
-		t.Fatal("expected error")
+func TestErrInvalidCidIs(t *testing.T) {
+	for i, test := range []struct {
+		err    error
+		target error
+	}{
+		{&ErrInvalidCid{}, ErrInvalidCid{}},
+		{ErrInvalidCid{}, &ErrInvalidCid{}},
+		{ErrInvalidCid{}, ErrInvalidCid{}},
+		{&ErrInvalidCid{}, &ErrInvalidCid{}},
+	} {
+		if !errors.Is(test.err, test.target) {
+			t.Fatalf("expected error to be ErrInvalidCid, case %d", i)
+		}
 	}
+}
 
-	is := errors.Is(err, ErrInvalidCid{})
-	if !is {
-		t.Fatal("expected error to be ErrInvalidCid")
+func TestErrInvalidCid(t *testing.T) {
+	run := func(cid Cid, err error) {
+		if err == nil {
+			t.Fatal("expected error")
+		}
+
+		if !strings.HasPrefix(err.Error(), "invalid cid: ") {
+			t.Fatal(`expected error message to contain "invalid cid: "`)
+		}
+
+		is := errors.Is(err, ErrInvalidCid{})
+		if !is {
+			t.Fatal("expected error to be ErrInvalidCid")
+		}
+
+		if !errors.Is(err, &ErrInvalidCid{}) {
+			t.Fatal("expected error to be &ErrInvalidCid")
+		}
 	}
+
+	run(Decode(""))
+	run(Decode("not-a-cid"))
+	run(Decode("bafyInvalid"))
+	run(Decode("QmdfTbBqBPQ7VNxZEYEj14VmRuZBkqFbiwReogJgS1zIII"))
+	run(Cast([]byte("invalid")))
+	run(Parse("not-a-cid"))
+	run(Parse("bafyInvalid"))
+	run(Parse("QmdfTbBqBPQ7VNxZEYEj14VmRuZBkqFbiwReogJgS1zIII"))
+	run(Parse(123))
 }