1 files changed, 94 insertions, 0 deletions
diff --git a/modules/templates/eval/eval_test.go b/modules/templates/eval/eval_test.go
new file mode 100644
index 0000000..3e68203
--- /dev/null
+++ b/modules/templates/eval/eval_test.go
@@ -0,0 +1,94 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package eval
+
+import (
+	"math"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func tokens(s string) (a []any) {
+	for _, v := range strings.Fields(s) {
+		a = append(a, v)
+	}
+	return a
+}
+
+func TestEval(t *testing.T) {
+	n, err := Expr(0, "/", 0.0)
+	require.NoError(t, err)
+	assert.True(t, math.IsNaN(n.Value.(float64)))
+
+	_, err = Expr(nil)
+	require.ErrorContains(t, err, "unsupported token type")
+	_, err = Expr([]string{})
+	require.ErrorContains(t, err, "unsupported token type")
+	_, err = Expr(struct{}{})
+	require.ErrorContains(t, err, "unsupported token type")
+
+	cases := []struct {
+		expr string
+		want any
+	}{
+		{"-1", int64(-1)},
+		{"1 + 2", int64(3)},
+		{"3 - 2 + 4", int64(5)},
+		{"1 + 2 * 3", int64(7)},
+		{"1 + ( 2 * 3 )", int64(7)},
+		{"( 1 + 2 ) * 3", int64(9)},
+		{"( 1 + 2.0 ) / 3", float64(1)},
+		{"sum( 1 , 2 , 3 , 4 )", int64(10)},
+		{"100 + sum( 1 , 2 + 3 , 0.0 ) / 2", float64(103)},
+		{"100 * 5 / ( 5 + 15 )", int64(25)},
+		{"9 == 5", int64(0)},
+		{"5 == 5", int64(1)},
+		{"9 != 5", int64(1)},
+		{"5 != 5", int64(0)},
+		{"9 > 5", int64(1)},
+		{"5 > 9", int64(0)},
+		{"5 >= 9", int64(0)},
+		{"9 >= 9", int64(1)},
+		{"9 < 5", int64(0)},
+		{"5 < 9", int64(1)},
+		{"9 <= 5", int64(0)},
+		{"5 <= 5", int64(1)},
+		{"1 and 2", int64(1)}, // Golang template definition: non-zero values are all truth
+		{"1 and 0", int64(0)},
+		{"0 and 0", int64(0)},
+		{"1 or 2", int64(1)},
+		{"1 or 0", int64(1)},
+		{"0 or 1", int64(1)},
+		{"0 or 0", int64(0)},
+		{"not 2 == 1", int64(1)},
+		{"not not ( 9 < 5 )", int64(0)},
+	}
+
+	for _, c := range cases {
+		n, err := Expr(tokens(c.expr)...)
+		require.NoError(t, err, "expr: %s", c.expr)
+		assert.Equal(t, c.want, n.Value)
+	}
+
+	bads := []struct {
+		expr   string
+		errMsg string
+	}{
+		{"0 / 0", "integer divide by zero"},
+		{"1 +", "num stack is empty"},
+		{"+ 1", "num stack is empty"},
+		{"( 1", "incomplete sub-expression"},
+		{"1 )", "op stack is empty"}, // can not find the corresponding open bracket after the stack becomes empty
+		{"1 , 2", "expect 1 value as final result"},
+		{"( 1 , 2 )", "too many values in one bracket"},
+		{"1 a 2", "unknown operator"},
+	}
+	for _, c := range bads {
+		_, err = Expr(tokens(c.expr)...)
+		require.ErrorContains(t, err, c.errMsg, "expr: %s", c.expr)
+	}
+}