diff --git a/lang/funcs/core/coremath/sqrt_func_test.go b/lang/funcs/core/coremath/sqrt_func_test.go
new file mode 100644
index 00000000..f7fb46d8
--- /dev/null
+++ b/lang/funcs/core/coremath/sqrt_func_test.go
@@ -0,0 +1,72 @@
+// Mgmt
+// Copyright (C) 2013-2018+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package coremath
+
+import (
+	"fmt"
+	"math"
+	"testing"
+
+	"github.com/purpleidea/mgmt/lang/types"
+)
+
+func testSqrtSuccess(input, sqrt float64) error {
+	inputVal := &types.FloatValue{V: input}
+
+	val, err := Sqrt([]types.Value{inputVal})
+	if err != nil {
+		return err
+	}
+	if val.Float() != sqrt {
+		return fmt.Errorf("Invalid output, expected %f, got %f", sqrt, val.Float())
+	}
+	return nil
+}
+
+func testSqrtError(input float64) error {
+	inputVal := &types.FloatValue{V: input}
+	_, err := Sqrt([]types.Value{inputVal})
+	if err == nil {
+		return fmt.Errorf("Expected error for input %f, got nil", input)
+	}
+	return nil
+}
+
+func TestSqrtValidInput(t *testing.T) {
+	values := map[float64]float64{
+		4.0:  2.0,
+		16.0: 4.0,
+		2.0:  math.Sqrt(2.0),
+	}
+
+	for input, sqrt := range values {
+		if err := testSqrtSuccess(input, sqrt); err != nil {
+			t.Error(err)
+		}
+	}
+}
+
+func TestSqrtInvalidInput(t *testing.T) {
+	values := []float64{-1.0}
+
+	for _, input := range values {
+		if err := testSqrtError(input); err != nil {
+			t.Error(err)
+		}
+	}
+}