diff --git a/clap/clap_test.go b/clap/clap_test.go
index 3820585..f6bceee 100644
--- a/clap/clap_test.go
+++ b/clap/clap_test.go
@@ -3,7 +3,6 @@ package clap_test
 import (
 	"errors"
 	"reflect"
-	"slices"
 	"testing"
 
 	"github.com/fred1268/go-clap/clap"
@@ -98,7 +97,8 @@ func TestMultipleMandatoryNotFound(t *testing.T) {
 			return
 		}
 		got := results.Mandatory
-		if len(got) != 2 || !slices.Contains(got, wanted[0]) || !slices.Contains(got, wanted[1]) {
+		if len(got) != 2 || (got[0] != wanted[0] && got[0] != wanted[1]) ||
+			(got[1] != wanted[0] && got[1] != wanted[1]) {
 			t.Errorf("wanted: '%v', got '%v'", wanted, got)
 			return
 		}
@@ -190,6 +190,9 @@ func TestLongName(t *testing.T) {
 	if !results.HasWarnings() || len(results.Ignored) != 4 {
 		t.Errorf("wrong error number / type")
 	}
+	if results.HasErrors() {
+		t.Errorf("unexpected errors")
+	}
 }
 
 func TestShortAndLong(t *testing.T) {
@@ -453,7 +456,7 @@ func TestMissingSliceArgument(t *testing.T) {
 	t.Logf("t: %v\n", results)
 }
 
-func TestUintParsing(t *testing.T) {
+func TestUintParsingError(t *testing.T) {
 	t.Parallel()
 	type config struct {
 		Uint uint `clap:"--uint"`
@@ -467,7 +470,7 @@ func TestUintParsing(t *testing.T) {
 	t.Logf("t: %v\n", results)
 }
 
-func TestFloatParsing(t *testing.T) {
+func TestFloatParsingError(t *testing.T) {
 	t.Parallel()
 	type config struct {
 		Float64 float64 `clap:"--float64"`
diff --git a/clap/tag.go b/clap/tag.go
index 827e598..a11e483 100644
--- a/clap/tag.go
+++ b/clap/tag.go
@@ -20,7 +20,7 @@ func getTrailingFieldDescription(tags []string, field reflect.StructField) (*fie
 		return nil, fmt.Errorf("field '%s': %w (got '%s', expected 'trailing')", field.Name,
 			ErrInvalidTag, field.Tag.Get("clap"))
 	}
-	if fieldDesc.Type.Kind() != reflect.String && fieldDesc.Type.Elem().Kind() != reflect.String {
+	if fieldDesc.Type.Kind() != reflect.Slice || fieldDesc.Type.Elem().Kind() != reflect.String {
 		return nil, fmt.Errorf("field '%s' should be a []string: %w", field.Name, ErrInvalidTag)
 	}
 	return fieldDesc, nil
diff --git a/clap/tag_test.go b/clap/tag_test.go
new file mode 100644
index 0000000..cbeace8
--- /dev/null
+++ b/clap/tag_test.go
@@ -0,0 +1,79 @@
+package clap_test
+
+import (
+	"testing"
+
+	"github.com/fred1268/go-clap/clap"
+)
+
+func TestNonEmptyTrailing(t *testing.T) {
+	t.Parallel()
+	type config struct {
+		Field    string   `clap:"--string"`
+		Trailing []string `clap:"trailing,-t"`
+	}
+	cfg := &config{}
+	var err error
+	var results *clap.Results
+	if results, err = clap.Parse([]string{"--string", "hello"}, cfg); err == nil {
+		t.Errorf("unexpected trailing: %s", err)
+	}
+	t.Logf("t: %v\n", results)
+}
+
+func TestNonStringTrailing(t *testing.T) {
+	t.Parallel()
+	type config struct {
+		Field    string `clap:"--string"`
+		Trailing int    `clap:"trailing"`
+	}
+	cfg := &config{}
+	var err error
+	var results *clap.Results
+	if results, err = clap.Parse([]string{"--string", "hello"}, cfg); err == nil {
+		t.Errorf("unexpected trailing: %s", err)
+	}
+	t.Logf("t: %v\n", results)
+}
+
+func TestInvalidShortName(t *testing.T) {
+	t.Parallel()
+	type config struct {
+		Field string `clap:",-s,foo,bar"`
+	}
+	cfg := &config{}
+	var err error
+	var results *clap.Results
+	if results, err = clap.Parse([]string{"-s", "hello"}, cfg); err == nil {
+		t.Errorf("unexpected valid shortname: %s", err)
+	}
+	t.Logf("t: %v\n", results)
+}
+
+func TestNoShortName(t *testing.T) {
+	t.Parallel()
+	type config struct {
+		Field string `clap:",-"`
+	}
+	cfg := &config{}
+	var err error
+	var results *clap.Results
+	if results, err = clap.Parse([]string{"-s", "hello"}, cfg); err == nil {
+		t.Errorf("unexpected valid shortname: %s", err)
+	}
+	t.Logf("t: %v\n", results)
+}
+
+func TestInvalidShortNameParameter(t *testing.T) {
+	t.Parallel()
+	type config struct {
+		Field string `clap:",-s,unexpected"`
+	}
+	cfg := &config{}
+	var err error
+	var results *clap.Results
+	if results, err = clap.Parse([]string{"-s", "hello"}, cfg); err == nil {
+		t.Errorf("unexpected valid shortname: %s", err)
+	}
+	t.Logf("t: %v\n", results)
+}