test(logic): put string_bytes/3 under test

x/logic/predicate/string_test.go

@@ -197,3 +197,125 @@ func TestReadString(t *testing.T) {
 		}
 	})
 }
+
+func TestStringBytes(t *testing.T) {
+	Convey("Given a test cases", t, func() {
+		cases := []struct {
+			program     string
+			query       string
+			wantError   error
+			wantSuccess bool
+		}{
+			// inspired from https://github.com/SWI-Prolog/swipl-devel/blob/V9.1.21/src/Tests/core/test_string.pl#L91
+			{
+				query:       "string_bytes(aap, [97, 97, 112], ascii).",
+				wantSuccess: true,
+			},
+			{
+				program:     `test :- string_bytes(aap, B, utf8), B == [97, 97, 112].`,
+				query:       "test.",
+				wantSuccess: true,
+			},
+			{
+				program:     `test :- string_bytes(S, [97, 97, 112], utf8), S == "aap".`,
+				query:       "test.",
+				wantSuccess: true,
+			},
+			{
+				program:     `test :- string_bytes(aap, B, 'utf-16be'), B == [0, 97, 0, 97, 0, 112].`,
+				query:       "test.",
+				wantSuccess: true,
+			},
+			{
+				program:     `test :- string_bytes(S, [0, 97, 0, 97, 0, 112], 'utf-16be'), S == "aap".`,
+				query:       "test.",
+				wantSuccess: true,
+			},
+			{
+				program:     `test :- string_bytes(aap, B, 'utf-16le'), B ==[97, 0, 97, 0, 112, 0].`,
+				query:       "test.",
+				wantSuccess: true,
+			},
+			{
+				program:     `test :- string_bytes(S, [97, 0, 97, 0, 112, 0], 'utf-16le'), S == "aap".`,
+				query:       "test.",
+				wantSuccess: true,
+			},
+			{
+				program:     `test :- string_bytes(今日は, B, utf8), B == [228,187,138,230,151,165,227,129,175].`,
+				query:       "test.",
+				wantSuccess: true,
+			},
+			{
+				program:     `test :- string_bytes(S, [228,187,138,230,151,165,227,129,175], utf8), S == "今日は".`,
+				query:       "test.",
+				wantSuccess: true,
+			},
+			{
+				program:     `test :- string_bytes(今日は, B, 'utf-16le'), B == [202,78,229,101,111,48].`,
+				query:       "test.",
+				wantSuccess: true,
+			},
+			{
+				program:     `test :- string_bytes(S, [202,78,229,101,111,48], 'utf-16le'), S == "今日は".`,
+				query:       "test.",
+				wantSuccess: true,
+			},
+			// error cases
+			{
+				query:       `string_bytes(_, [202,78,229,101,111,48], foo).`,
+				wantSuccess: false,
+				wantError:   fmt.Errorf("string_bytes/3: invalid encoding: foo"),
+			},
+		}
+		for nc, tc := range cases {
+			Convey(fmt.Sprintf("Given the query #%d: %s", nc, tc.query), func() {
+				Convey("and a context", func() {
+					db := tmdb.NewMemDB()
+					stateStore := store.NewCommitMultiStore(db)
+					ctx := sdk.NewContext(stateStore, tmproto.Header{}, false, log.NewNopLogger())
+
+					Convey("and a vm", func() {
+						interpreter := testutil.NewLightInterpreterMust(ctx)
+						interpreter.Register3(engine.NewAtom("string_bytes"), StringBytes)
+
+						Convey("and a program", func() {
+							err := interpreter.Compile(ctx, tc.program)
+							So(err, ShouldBeNil)
+
+							Convey("When the predicate is called", func() {
+								sols, err := interpreter.QueryContext(ctx, tc.query)
+
+								Convey("Then the error should be nil", func() {
+									So(err, ShouldBeNil)
+									So(sols, ShouldNotBeNil)
+
+									Convey("and the result should be as expected", func() {
+										if tc.wantError != nil {
+											sols.Next()
+											So(sols.Err(), ShouldNotBeNil)
+											So(sols.Err().Error(), ShouldEqual, tc.wantError.Error())
+										} else {
+											nb := 0
+											for sols.Next() {
+												m := types.TermResults{}
+												So(sols.Scan(m), ShouldBeNil)
+												nb++
+											}
+											So(sols.Err(), ShouldBeNil)
+											if tc.wantSuccess {
+												So(nb, ShouldEqual, 1)
+											} else {
+												So(nb, ShouldEqual, 0)
+											}
+										}
+									})
+								})
+							})
+						})
+					})
+				})
+			})
+		}
+	})
+}