add modulus function support

examples/functions/mod/function.tf

@@ -0,0 +1,11 @@
+# Return the remainder of 4 / 2:
+provider::stdlib::mod(4, 2)
+# result: 0
+
+# Return the remainder of 5 / 3:
+provider::stdlib::mod(5, 3)
+# result: 2
+
+# Return the remainder of 10 / 4.75:
+provider::stdlib::mod(10, 4.75)
+# result: 0.5

stdlib/number/mod_test.go

@@ -0,0 +1,66 @@
+package numberfunc_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/hashicorp/terraform-plugin-framework/attr"
+	"github.com/hashicorp/terraform-plugin-framework/function"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+
+	numberfunc "github.com/mschuchard/terraform-provider-stdlib/stdlib/number"
+)
+
+func TestModFunction(test *testing.T) {
+	test.Parallel()
+
+	standardTestCases := map[string]struct {
+		request  function.RunRequest
+		expected function.RunResponse
+	}{
+		"zero": {
+			request: function.RunRequest{
+				Arguments: function.NewArgumentsData([]attr.Value{types.Float64Value(4), types.Float64Value(2)}),
+			},
+			expected: function.RunResponse{
+				Result: function.NewResultData(types.Float64Value(0)),
+			},
+		},
+		"integer": {
+			request: function.RunRequest{
+				Arguments: function.NewArgumentsData([]attr.Value{types.Float64Value(5), types.Float64Value(3)}),
+			},
+			expected: function.RunResponse{
+				Result: function.NewResultData(types.Float64Value(2)),
+			},
+		},
+		"float": {
+			request: function.RunRequest{
+				Arguments: function.NewArgumentsData([]attr.Value{types.Float64Value(10), types.Float64Value(4.75)}),
+			},
+			expected: function.RunResponse{
+				Result: function.NewResultData(types.Float64Value(0.5)),
+			},
+		},
+	}
+
+	for name, testCase := range standardTestCases {
+		test.Run(name, func(test *testing.T) {
+			// initialize result
+			result := function.RunResponse{Result: function.NewResultData(types.Float64Unknown())}
+
+			// execute function and store result
+			numberfunc.NewModFunction().Run(context.Background(), testCase.request, &result)
+
+			// compare results
+			if !result.Error.Equal(testCase.expected.Error) {
+				test.Errorf("expected value: %s", testCase.expected.Error)
+				test.Errorf("actual value: %s", result.Error)
+			}
+			if !result.Result.Equal(testCase.expected.Result) {
+				test.Errorf("expected value: %+q", testCase.expected.Result.Value())
+				test.Errorf("actual value: %+q", result.Result.Value())
+			}
+		})
+	}
+}

stdlib/provider.go

@@ -89,6 +89,7 @@ func (*stdlibProvider) DataSources(_ context.Context) []func() datasource.DataSo
 func (*stdlibProvider) Functions(_ context.Context) []func() function.Function {
 	return []func() function.Function{
 		numberfunc.NewExpFunction,
+		numberfunc.NewModFunction,
 		stringfunc.NewCutFunction,
 		stringfunc.NewLastCharFunction,
 	}