[#150] policy: Check for redundant selectors and filters

Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

netmap/policy_decode_test.go

@@ -0,0 +1,61 @@
+package netmap
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestDecodeString(t *testing.T) {
+	testCases := []string{
+		`REP 1 IN X
+CBF 1
+SELECT 2 IN SAME Location FROM * AS X`,
+
+		`REP 1 IN X
+REP 2 IN Y
+CBF 1
+SELECT 2 FROM * AS X
+SELECT 3 FROM * AS Y`,
+
+		`REP 1 IN X
+SELECT 2 IN City FROM Good AS X
+FILTER Country EQ RU AS FromRU
+FILTER Country EQ EN AS FromEN
+FILTER @FromRU AND @FromEN AND Rating GT 7 AS Good`,
+
+		`REP 7 IN SPB
+SELECT 1 IN City FROM SPBSSD AS SPB
+FILTER City EQ SPB AND SSD EQ true OR City EQ SPB AND Rating GE 5 AS SPBSSD`,
+
+		`REP 7 IN SPB
+SELECT 1 IN City FROM SPBSSD AS SPB
+FILTER NOT (NOT (City EQ SPB) AND SSD EQ true OR City EQ SPB AND Rating GE 5) AS SPBSSD`,
+
+		`UNIQUE
+REP 1
+REP 1`,
+	}
+
+	var p PlacementPolicy
+
+	for _, testCase := range testCases {
+		require.NoError(t, p.DecodeString(testCase), "unable parse %s", testCase)
+		var b strings.Builder
+		require.NoError(t, p.WriteStringTo(&b))
+		require.Equal(t, testCase, b.String())
+	}
+
+	invalidTestCases := map[string]error{
+		`?REP 1`:                     errSyntaxError,
+		`REP 1 trailing garbage`:     errSyntaxError,
+		`REP 1 SELECT 4 FROM * `:     errUnnamedSelector,
+		`REP 1 SELECT 4 FROM * AS X`: errRedundantSelector,
+		`REP 1 IN X REP 2 SELECT 4 FROM * AS X FILTER 'UN-LOCODE' EQ 'RU LED' AS F`: errRedundantFilter,
+	}
+
+	for i := range invalidTestCases {
+		require.ErrorIs(t, p.DecodeString(i), invalidTestCases[i], "#%s", i)
+	}
+}