add tests for length

hcl2template/function/length.go

@@ -51,3 +51,9 @@ var LengthFunc = function.New(&function.Spec{
 		}
 	},
 })
+
+// Length returns the number of elements in the given collection or number of
+// Unicode characters in the given string.
+func Length(collection cty.Value) (cty.Value, error) {
+	return LengthFunc.Call([]cty.Value{collection})
+}

hcl2template/function/length_test.go

@@ -0,0 +1,139 @@
+package function
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/zclconf/go-cty/cty"
+)
+
+func TestLength(t *testing.T) {
+	tests := []struct {
+		Value cty.Value
+		Want  cty.Value
+	}{
+		{
+			cty.ListValEmpty(cty.Number),
+			cty.NumberIntVal(0),
+		},
+		{
+			cty.ListVal([]cty.Value{cty.True}),
+			cty.NumberIntVal(1),
+		},
+		{
+			cty.ListVal([]cty.Value{cty.UnknownVal(cty.Bool)}),
+			cty.NumberIntVal(1),
+		},
+		{
+			cty.SetValEmpty(cty.Number),
+			cty.NumberIntVal(0),
+		},
+		{
+			cty.SetVal([]cty.Value{cty.True}),
+			cty.NumberIntVal(1),
+		},
+		{
+			cty.MapValEmpty(cty.Bool),
+			cty.NumberIntVal(0),
+		},
+		{
+			cty.MapVal(map[string]cty.Value{"hello": cty.True}),
+			cty.NumberIntVal(1),
+		},
+		{
+			cty.EmptyTupleVal,
+			cty.NumberIntVal(0),
+		},
+		{
+			cty.UnknownVal(cty.EmptyTuple),
+			cty.NumberIntVal(0),
+		},
+		{
+			cty.TupleVal([]cty.Value{cty.True}),
+			cty.NumberIntVal(1),
+		},
+		{
+			cty.EmptyObjectVal,
+			cty.NumberIntVal(0),
+		},
+		{
+			cty.UnknownVal(cty.EmptyObject),
+			cty.NumberIntVal(0),
+		},
+		{
+			cty.ObjectVal(map[string]cty.Value{"true": cty.True}),
+			cty.NumberIntVal(1),
+		},
+		{
+			cty.UnknownVal(cty.List(cty.Bool)),
+			cty.UnknownVal(cty.Number),
+		},
+		{
+			cty.DynamicVal,
+			cty.UnknownVal(cty.Number),
+		},
+		{
+			cty.StringVal("hello"),
+			cty.NumberIntVal(5),
+		},
+		{
+			cty.StringVal(""),
+			cty.NumberIntVal(0),
+		},
+		{
+			cty.StringVal("1"),
+			cty.NumberIntVal(1),
+		},
+		{
+			cty.StringVal("Живой Журнал"),
+			cty.NumberIntVal(12),
+		},
+		{
+			// note that the dieresis here is intentionally a combining
+			// ligature.
+			cty.StringVal("noël"),
+			cty.NumberIntVal(4),
+		},
+		{
+			// The Es in this string has three combining acute accents.
+			// This tests something that NFC-normalization cannot collapse
+			// into a single precombined codepoint, since otherwise we might
+			// be cheating and relying on the single-codepoint forms.
+			cty.StringVal("wé́́é́́é́́!"),
+			cty.NumberIntVal(5),
+		},
+		{
+			// Go's normalization forms don't handle this ligature, so we
+			// will produce the wrong result but this is now a compatibility
+			// constraint and so we'll test it.
+			cty.StringVal("baffle"),
+			cty.NumberIntVal(4),
+		},
+		{
+			cty.StringVal("😸😾"),
+			cty.NumberIntVal(2),
+		},
+		{
+			cty.UnknownVal(cty.String),
+			cty.UnknownVal(cty.Number),
+		},
+		{
+			cty.DynamicVal,
+			cty.UnknownVal(cty.Number),
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(fmt.Sprintf("Length(%#v)", test.Value), func(t *testing.T) {
+			got, err := Length(test.Value)
+
+			if err != nil {
+				t.Fatalf("unexpected error: %s", err)
+			}
+
+			if !got.RawEquals(test.Want) {
+				t.Errorf("wrong result\ngot:  %#v\nwant: %#v", got, test.Want)
+			}
+		})
+	}
+}