public void testIntervalOps(S2LatLngRect x, S2LatLngRect y, String expectedRelation,
                                    S2LatLngRect expectedUnion, S2LatLngRect expectedIntersection)
        {
            // Test all of the interval operations on the given pair of intervals.
            // "expected_relation" is a sequence of "T" and "F" characters corresponding
            // to the expected results of Contains(), InteriorContains(), Intersects(),
            // and InteriorIntersects() respectively.

            assertEquals(x.Contains(y), expectedRelation[0] == 'T');
            assertEquals(x.InteriorContains(y), expectedRelation[1] == 'T');
            assertEquals(x.Intersects(y), expectedRelation[2] == 'T');
            assertEquals(x.InteriorIntersects(y), expectedRelation[3] == 'T');

            assertEquals(x.Contains(y), x.Union(y).Equals(x));
            assertEquals(x.Intersects(y), !x.Intersection(y).IsEmpty);

            assertTrue(x.Union(y).Equals(expectedUnion));
            assertTrue(x.Intersection(y).Equals(expectedIntersection));

            if (y.Size == S2LatLng.FromRadians(0, 0))
            {
                var r = x.AddPoint(y.Lo);
                assertTrue(r == expectedUnion);
            }
        }
Example #2
0
    private static void TestIntervalOps(S2LatLngRect x, S2LatLngRect y, string expected_relation, S2LatLngRect expected_union, S2LatLngRect expected_intersection)
    {
        // Test all of the interval operations on the given pair of intervals.
        // "expected_relation" is a sequence of "T" and "F" characters corresponding
        // to the expected results of Contains(), InteriorContains(), Intersects(),
        // and InteriorIntersects() respectively.

        Assert.Equal(x.Contains(y), expected_relation[0] == 'T');
        Assert.Equal(x.InteriorContains(y), expected_relation[1] == 'T');
        Assert.Equal(x.Intersects(y), expected_relation[2] == 'T');
        Assert.Equal(x.InteriorIntersects(y), expected_relation[3] == 'T');

        Assert.Equal(x.Contains(y), x.Union(y) == x);
        Assert.Equal(x.Intersects(y), !x.Intersection(y).IsEmpty());

        Assert.Equal(x.Union(y), expected_union);
        Assert.Equal(x.Intersection(y), expected_intersection);

        if (y.Size() == S2LatLng.FromRadians(0, 0))
        {
            S2LatLngRect r = x;
            r.AddPoint(y.Lo());
            Assert.Equal(r, expected_union);
        }
    }
        public void testIntervalOps(S2LatLngRect x, S2LatLngRect y, String expectedRelation,
                                    S2LatLngRect expectedUnion, S2LatLngRect expectedIntersection)
        {
            // Test all of the interval operations on the given pair of intervals.
            // "expected_relation" is a sequence of "T" and "F" characters corresponding
            // to the expected results of Contains(), InteriorContains(), Intersects(),
            // and InteriorIntersects() respectively.

            assertEquals(x.Contains(y), expectedRelation[0] == 'T');
            assertEquals(x.InteriorContains(y), expectedRelation[1] == 'T');
            assertEquals(x.Intersects(y), expectedRelation[2] == 'T');
            assertEquals(x.InteriorIntersects(y), expectedRelation[3] == 'T');

            assertEquals(x.Contains(y), x.Union(y).Equals(x));
            assertEquals(x.Intersects(y), !x.Intersection(y).IsEmpty);

            assertTrue(x.Union(y).Equals(expectedUnion));
            assertTrue(x.Intersection(y).Equals(expectedIntersection));

            if (y.Size == S2LatLng.FromRadians(0, 0))
            {
                var r = x.AddPoint(y.Lo);
                assertTrue(r == expectedUnion);
            }
        }
        public void testBasic()
        {
            // Most of the S2LatLngRect methods have trivial implementations that
            // use the R1Interval and S1Interval classes, so most of the testing
            // is done in those unit tests.

            // Test basic properties of empty and full caps.
            var empty = S2LatLngRect.Empty;
            var full = S2LatLngRect.Full;
            assertTrue(empty.IsValid);
            assertTrue(empty.IsEmpty);
            assertTrue(full.IsValid);
            assertTrue(full.IsFull);

            // assertTrue various constructors and accessor methods.
            var d1 = rectFromDegrees(-90, 0, -45, 180);
            assertDoubleNear(d1.LatLo.Degrees, -90);
            assertDoubleNear(d1.LatHi.Degrees, -45);
            assertDoubleNear(d1.LngLo.Degrees, 0);
            assertDoubleNear(d1.LngHi.Degrees, 180);
            assertTrue(d1.Lat.Equals(new R1Interval(-S2.PiOver2, -S2.PiOver4)));
            assertTrue(d1.Lng.Equals(new S1Interval(0, S2.Pi)));

            // FromCenterSize()
            assertTrue(
                S2LatLngRect.FromCenterSize(S2LatLng.FromDegrees(80, 170), S2LatLng.FromDegrees(40, 60))
                            .ApproxEquals(rectFromDegrees(60, 140, 90, -160)));
            assertTrue(S2LatLngRect
                           .FromCenterSize(S2LatLng.FromDegrees(10, 40), S2LatLng.FromDegrees(210, 400)).IsFull);
            assertTrue(
                S2LatLngRect.FromCenterSize(S2LatLng.FromDegrees(-90, 180), S2LatLng.FromDegrees(20, 50))
                            .ApproxEquals(rectFromDegrees(-90, 155, -80, -155)));

            // FromPoint(), FromPointPair()
            assertEquals(S2LatLngRect.FromPoint(d1.Lo), new S2LatLngRect(d1.Lo, d1.Lo));
            assertEquals(
                S2LatLngRect.FromPointPair(S2LatLng.FromDegrees(-35, -140), S2LatLng.FromDegrees(15, 155)),
                rectFromDegrees(-35, 155, 15, -140));
            assertEquals(
                S2LatLngRect.FromPointPair(S2LatLng.FromDegrees(25, -70), S2LatLng.FromDegrees(-90, 80)),
                rectFromDegrees(-90, -70, 25, 80));

            // GetCenter(), GetVertex(), Contains(S2LatLng), InteriorContains(S2LatLng).
            var eqM180 = S2LatLng.FromRadians(0, -S2.Pi);
            var northPole = S2LatLng.FromRadians(S2.PiOver2, 0);
            var r1 = new S2LatLngRect(eqM180, northPole);

            assertEquals(r1.Center, S2LatLng.FromRadians(S2.PiOver4, -S2.PiOver2));
            assertEquals(r1.GetVertex(0), S2LatLng.FromRadians(0, S2.Pi));
            assertEquals(r1.GetVertex(1), S2LatLng.FromRadians(0, 0));
            assertEquals(r1.GetVertex(2), S2LatLng.FromRadians(S2.PiOver2, 0));
            assertEquals(r1.GetVertex(3), S2LatLng.FromRadians(S2.PiOver2, S2.Pi));
            assertTrue(r1.Contains(S2LatLng.FromDegrees(30, -45)));
            assertTrue(!r1.Contains(S2LatLng.FromDegrees(30, 45)));
            assertTrue(!r1.InteriorContains(eqM180) && !r1.InteriorContains(northPole));
            assertTrue(r1.Contains(new S2Point(0.5, -0.3, 0.1)));
            assertTrue(!r1.Contains(new S2Point(0.5, 0.2, 0.1)));

            // Make sure that GetVertex() returns vertices in CCW order.
            for (var i = 0; i < 4; ++i)
            {
                var lat = S2.PiOver4*(i - 2);
                var lng = S2.PiOver2*(i - 2) + 0.2;
                var r = new S2LatLngRect(new R1Interval(lat, lat + S2.PiOver4), new S1Interval(
                                                                                   Math.IEEERemainder(lng, 2*S2.Pi), Math.IEEERemainder(lng + S2.PiOver2, 2*S2.Pi)));
                for (var k = 0; k < 4; ++k)
                {
                    assertTrue(
                        S2.SimpleCcw(r.GetVertex((k - 1) & 3).ToPoint(), r.GetVertex(k).ToPoint(),
                                     r.GetVertex((k + 1) & 3).ToPoint()));
                }
            }

            // Contains(S2LatLngRect), InteriorContains(S2LatLngRect),
            // Intersects(), InteriorIntersects(), Union(), Intersection().
            //
            // Much more testing of these methods is done in s1interval_unittest
            // and r1interval_unittest.

            var r1Mid = rectFromDegrees(45, -90, 45, -90);
            var reqM180 = new S2LatLngRect(eqM180, eqM180);
            var rNorthPole = new S2LatLngRect(northPole, northPole);

            testIntervalOps(r1, r1Mid, "TTTT", r1, r1Mid);
            testIntervalOps(r1, reqM180, "TFTF", r1, reqM180);
            testIntervalOps(r1, rNorthPole, "TFTF", r1, rNorthPole);

            assertTrue(r1.Equals(rectFromDegrees(0, -180, 90, 0)));
            testIntervalOps(r1, rectFromDegrees(-10, -1, 1, 20), "FFTT", rectFromDegrees(-10, -180, 90, 20),
                            rectFromDegrees(0, -1, 1, 0));
            testIntervalOps(r1, rectFromDegrees(-10, -1, 0, 20), "FFTF", rectFromDegrees(-10, -180, 90, 20),
                            rectFromDegrees(0, -1, 0, 0));
            testIntervalOps(r1, rectFromDegrees(-10, 0, 1, 20), "FFTF", rectFromDegrees(-10, -180, 90, 20),
                            rectFromDegrees(0, 0, 1, 0));

            testIntervalOps(rectFromDegrees(-15, -160, -15, -150), rectFromDegrees(20, 145, 25, 155),
                            "FFFF", rectFromDegrees(-15, 145, 25, -150), empty);
            testIntervalOps(rectFromDegrees(70, -10, 90, -140), rectFromDegrees(60, 175, 80, 5), "FFTT",
                            rectFromDegrees(60, -180, 90, 180), rectFromDegrees(70, 175, 80, 5));

            // assertTrue that the intersection of two rectangles that overlap in
            // latitude
            // but not longitude is valid, and vice versa.
            testIntervalOps(rectFromDegrees(12, 30, 60, 60), rectFromDegrees(0, 0, 30, 18), "FFFF",
                            rectFromDegrees(0, 0, 60, 60), empty);
            testIntervalOps(rectFromDegrees(0, 0, 18, 42), rectFromDegrees(30, 12, 42, 60), "FFFF",
                            rectFromDegrees(0, 0, 42, 60), empty);

            // AddPoint()
            var p = S2LatLngRect.Empty;
            p = p.AddPoint(S2LatLng.FromDegrees(0, 0));
            p = p.AddPoint(S2LatLng.FromRadians(0, -S2.PiOver2));
            p = p.AddPoint(S2LatLng.FromRadians(S2.PiOver4, -S2.Pi));
            p = p.AddPoint(new S2Point(0, 0, 1));
            assertTrue(p.Equals(r1));

            // Expanded()
            assertTrue(
                rectFromDegrees(70, 150, 80, 170).Expanded(S2LatLng.FromDegrees(20, 30)).ApproxEquals(
                    rectFromDegrees(50, 120, 90, -160)));
            assertTrue(S2LatLngRect.Empty.Expanded(S2LatLng.FromDegrees(20, 30)).IsEmpty);
            assertTrue(S2LatLngRect.Full.Expanded(S2LatLng.FromDegrees(20, 30)).IsFull);
            assertTrue(
                rectFromDegrees(-90, 170, 10, 20).Expanded(S2LatLng.FromDegrees(30, 80)).ApproxEquals(
                    rectFromDegrees(-90, -180, 40, 180)));

            // ConvolveWithCap()
            var llr1 =
                new S2LatLngRect(S2LatLng.FromDegrees(0, 170), S2LatLng.FromDegrees(0, -170))
                    .ConvolveWithCap(S1Angle.FromDegrees(15));
            var llr2 =
                new S2LatLngRect(S2LatLng.FromDegrees(-15, 155), S2LatLng.FromDegrees(15, -155));
            assertTrue(llr1.ApproxEquals(llr2));

            llr1 = new S2LatLngRect(S2LatLng.FromDegrees(60, 150), S2LatLng.FromDegrees(80, 10))
                .ConvolveWithCap(S1Angle.FromDegrees(15));
            llr2 = new S2LatLngRect(S2LatLng.FromDegrees(45, -180), S2LatLng.FromDegrees(90, 180));
            assertTrue(llr1.ApproxEquals(llr2));

            // GetCapBound(), bounding cap at center is smaller:
            assertTrue(new S2LatLngRect(S2LatLng.FromDegrees(-45, -45), S2LatLng.FromDegrees(45, 45)).CapBound.ApproxEquals(S2Cap.FromAxisHeight(new S2Point(1, 0, 0), 0.5)));
            // GetCapBound(), bounding cap at north pole is smaller:
            assertTrue(new S2LatLngRect(S2LatLng.FromDegrees(88, -80), S2LatLng.FromDegrees(89, 80)).CapBound.ApproxEquals(S2Cap.FromAxisAngle(new S2Point(0, 0, 1), S1Angle.FromDegrees(2))));
            // GetCapBound(), longitude span > 180 degrees:
            assertTrue(
                new S2LatLngRect(S2LatLng.FromDegrees(-30, -150), S2LatLng.FromDegrees(-10, 50)).CapBound
                    .ApproxEquals(S2Cap.FromAxisAngle(new S2Point(0, 0, -1), S1Angle.FromDegrees(80))));

            // Contains(S2Cell), MayIntersect(S2Cell), Intersects(S2Cell)

            // Special cases.
            testCellOps(empty, S2Cell.FromFacePosLevel(3, (byte)0, 0), 0);
            testCellOps(full, S2Cell.FromFacePosLevel(2, (byte)0, 0), 4);
            testCellOps(full, S2Cell.FromFacePosLevel(5, (byte)0, 25), 4);

            // This rectangle includes the first quadrant of face 0. It's expanded
            // slightly because cell bounding rectangles are slightly conservative.
            var r4 = rectFromDegrees(-45.1, -45.1, 0.1, 0.1);
            testCellOps(r4, S2Cell.FromFacePosLevel(0, (byte)0, 0), 3);
            testCellOps(r4, S2Cell.FromFacePosLevel(0, (byte)0, 1), 4);
            testCellOps(r4, S2Cell.FromFacePosLevel(1, (byte)0, 1), 0);

            // This rectangle intersects the first quadrant of face 0.
            var r5 = rectFromDegrees(-10, -45, 10, 0);
            testCellOps(r5, S2Cell.FromFacePosLevel(0, (byte)0, 0), 3);
            testCellOps(r5, S2Cell.FromFacePosLevel(0, (byte)0, 1), 3);
            testCellOps(r5, S2Cell.FromFacePosLevel(1, (byte)0, 1), 0);

            // Rectangle consisting of a single point.
            testCellOps(rectFromDegrees(4, 4, 4, 4), S2Cell.FromFacePosLevel(0, (byte)0, 0), 3);

            // Rectangles that intersect the bounding rectangle of a face
            // but not the face itself.
            testCellOps(rectFromDegrees(41, -87, 42, -79), S2Cell.FromFacePosLevel(2, (byte)0, 0), 1);
            testCellOps(rectFromDegrees(-41, 160, -40, -160), S2Cell.FromFacePosLevel(5, (byte)0, 0), 1);
            {
                // This is the leaf cell at the top right hand corner of face 0.
                // It has two angles of 60 degrees and two of 120 degrees.
                var cell0tr = new S2Cell(new S2Point(1 + 1e-12, 1, 1));
                var bound0tr = cell0tr.RectBound;
                var v0 = new S2LatLng(cell0tr.GetVertexRaw(0));
                testCellOps(
                    rectFromDegrees(v0.Lat.Degrees - 1e-8, v0.Lng.Degrees - 1e-8,
                                    v0.Lat.Degrees - 2e-10, v0.Lng.Degrees + 1e-10), cell0tr, 1);
            }

            // Rectangles that intersect a face but where no vertex of one region
            // is contained by the other region. The first one passes through
            // a corner of one of the face cells.
            testCellOps(rectFromDegrees(-37, -70, -36, -20), S2Cell.FromFacePosLevel(5, (byte)0, 0), 2);
            {
                // These two intersect like a diamond and a square.
                var cell202 = S2Cell.FromFacePosLevel(2, (byte)0, 2);
                var bound202 = cell202.RectBound;
                testCellOps(
                    rectFromDegrees(bound202.Lo.Lat.Degrees + 3, bound202.Lo.Lng.Degrees + 3,
                                    bound202.Hi.Lat.Degrees - 3, bound202.Hi.Lng.Degrees - 3), cell202, 2);
            }
        }
        public void testBasic()
        {
            // Most of the S2LatLngRect methods have trivial implementations that
            // use the R1Interval and S1Interval classes, so most of the testing
            // is done in those unit tests.

            // Test basic properties of empty and full caps.
            var empty = S2LatLngRect.Empty;
            var full  = S2LatLngRect.Full;

            assertTrue(empty.IsValid);
            assertTrue(empty.IsEmpty);
            assertTrue(full.IsValid);
            assertTrue(full.IsFull);

            // assertTrue various constructors and accessor methods.
            var d1 = rectFromDegrees(-90, 0, -45, 180);

            assertDoubleNear(d1.LatLo.Degrees, -90);
            assertDoubleNear(d1.LatHi.Degrees, -45);
            assertDoubleNear(d1.LngLo.Degrees, 0);
            assertDoubleNear(d1.LngHi.Degrees, 180);
            assertTrue(d1.Lat.Equals(new R1Interval(-S2.PiOver2, -S2.PiOver4)));
            assertTrue(d1.Lng.Equals(new S1Interval(0, S2.Pi)));

            // FromCenterSize()
            assertTrue(
                S2LatLngRect.FromCenterSize(S2LatLng.FromDegrees(80, 170), S2LatLng.FromDegrees(40, 60))
                .ApproxEquals(rectFromDegrees(60, 140, 90, -160)));
            assertTrue(S2LatLngRect
                       .FromCenterSize(S2LatLng.FromDegrees(10, 40), S2LatLng.FromDegrees(210, 400)).IsFull);
            assertTrue(
                S2LatLngRect.FromCenterSize(S2LatLng.FromDegrees(-90, 180), S2LatLng.FromDegrees(20, 50))
                .ApproxEquals(rectFromDegrees(-90, 155, -80, -155)));

            // FromPoint(), FromPointPair()
            assertEquals(S2LatLngRect.FromPoint(d1.Lo), new S2LatLngRect(d1.Lo, d1.Lo));
            assertEquals(
                S2LatLngRect.FromPointPair(S2LatLng.FromDegrees(-35, -140), S2LatLng.FromDegrees(15, 155)),
                rectFromDegrees(-35, 155, 15, -140));
            assertEquals(
                S2LatLngRect.FromPointPair(S2LatLng.FromDegrees(25, -70), S2LatLng.FromDegrees(-90, 80)),
                rectFromDegrees(-90, -70, 25, 80));

            // GetCenter(), GetVertex(), Contains(S2LatLng), InteriorContains(S2LatLng).
            var eqM180    = S2LatLng.FromRadians(0, -S2.Pi);
            var northPole = S2LatLng.FromRadians(S2.PiOver2, 0);
            var r1        = new S2LatLngRect(eqM180, northPole);

            assertEquals(r1.Center, S2LatLng.FromRadians(S2.PiOver4, -S2.PiOver2));
            assertEquals(r1.GetVertex(0), S2LatLng.FromRadians(0, S2.Pi));
            assertEquals(r1.GetVertex(1), S2LatLng.FromRadians(0, 0));
            assertEquals(r1.GetVertex(2), S2LatLng.FromRadians(S2.PiOver2, 0));
            assertEquals(r1.GetVertex(3), S2LatLng.FromRadians(S2.PiOver2, S2.Pi));
            assertTrue(r1.Contains(S2LatLng.FromDegrees(30, -45)));
            assertTrue(!r1.Contains(S2LatLng.FromDegrees(30, 45)));
            assertTrue(!r1.InteriorContains(eqM180) && !r1.InteriorContains(northPole));
            assertTrue(r1.Contains(new S2Point(0.5, -0.3, 0.1)));
            assertTrue(!r1.Contains(new S2Point(0.5, 0.2, 0.1)));

            // Make sure that GetVertex() returns vertices in CCW order.
            for (var i = 0; i < 4; ++i)
            {
                var lat = S2.PiOver4 * (i - 2);
                var lng = S2.PiOver2 * (i - 2) + 0.2;
                var r   = new S2LatLngRect(new R1Interval(lat, lat + S2.PiOver4), new S1Interval(
                                               Math.IEEERemainder(lng, 2 * S2.Pi), Math.IEEERemainder(lng + S2.PiOver2, 2 * S2.Pi)));
                for (var k = 0; k < 4; ++k)
                {
                    assertTrue(
                        S2.SimpleCcw(r.GetVertex((k - 1) & 3).ToPoint(), r.GetVertex(k).ToPoint(),
                                     r.GetVertex((k + 1) & 3).ToPoint()));
                }
            }

            // Contains(S2LatLngRect), InteriorContains(S2LatLngRect),
            // Intersects(), InteriorIntersects(), Union(), Intersection().
            //
            // Much more testing of these methods is done in s1interval_unittest
            // and r1interval_unittest.

            var r1Mid      = rectFromDegrees(45, -90, 45, -90);
            var reqM180    = new S2LatLngRect(eqM180, eqM180);
            var rNorthPole = new S2LatLngRect(northPole, northPole);

            testIntervalOps(r1, r1Mid, "TTTT", r1, r1Mid);
            testIntervalOps(r1, reqM180, "TFTF", r1, reqM180);
            testIntervalOps(r1, rNorthPole, "TFTF", r1, rNorthPole);

            assertTrue(r1.Equals(rectFromDegrees(0, -180, 90, 0)));
            testIntervalOps(r1, rectFromDegrees(-10, -1, 1, 20), "FFTT", rectFromDegrees(-10, -180, 90, 20),
                            rectFromDegrees(0, -1, 1, 0));
            testIntervalOps(r1, rectFromDegrees(-10, -1, 0, 20), "FFTF", rectFromDegrees(-10, -180, 90, 20),
                            rectFromDegrees(0, -1, 0, 0));
            testIntervalOps(r1, rectFromDegrees(-10, 0, 1, 20), "FFTF", rectFromDegrees(-10, -180, 90, 20),
                            rectFromDegrees(0, 0, 1, 0));

            testIntervalOps(rectFromDegrees(-15, -160, -15, -150), rectFromDegrees(20, 145, 25, 155),
                            "FFFF", rectFromDegrees(-15, 145, 25, -150), empty);
            testIntervalOps(rectFromDegrees(70, -10, 90, -140), rectFromDegrees(60, 175, 80, 5), "FFTT",
                            rectFromDegrees(60, -180, 90, 180), rectFromDegrees(70, 175, 80, 5));

            // assertTrue that the intersection of two rectangles that overlap in
            // latitude
            // but not longitude is valid, and vice versa.
            testIntervalOps(rectFromDegrees(12, 30, 60, 60), rectFromDegrees(0, 0, 30, 18), "FFFF",
                            rectFromDegrees(0, 0, 60, 60), empty);
            testIntervalOps(rectFromDegrees(0, 0, 18, 42), rectFromDegrees(30, 12, 42, 60), "FFFF",
                            rectFromDegrees(0, 0, 42, 60), empty);

            // AddPoint()
            var p = S2LatLngRect.Empty;

            p = p.AddPoint(S2LatLng.FromDegrees(0, 0));
            p = p.AddPoint(S2LatLng.FromRadians(0, -S2.PiOver2));
            p = p.AddPoint(S2LatLng.FromRadians(S2.PiOver4, -S2.Pi));
            p = p.AddPoint(new S2Point(0, 0, 1));
            assertTrue(p.Equals(r1));

            // Expanded()
            assertTrue(
                rectFromDegrees(70, 150, 80, 170).Expanded(S2LatLng.FromDegrees(20, 30)).ApproxEquals(
                    rectFromDegrees(50, 120, 90, -160)));
            assertTrue(S2LatLngRect.Empty.Expanded(S2LatLng.FromDegrees(20, 30)).IsEmpty);
            assertTrue(S2LatLngRect.Full.Expanded(S2LatLng.FromDegrees(20, 30)).IsFull);
            assertTrue(
                rectFromDegrees(-90, 170, 10, 20).Expanded(S2LatLng.FromDegrees(30, 80)).ApproxEquals(
                    rectFromDegrees(-90, -180, 40, 180)));

            // ConvolveWithCap()
            var llr1 =
                new S2LatLngRect(S2LatLng.FromDegrees(0, 170), S2LatLng.FromDegrees(0, -170))
                .ConvolveWithCap(S1Angle.FromDegrees(15));
            var llr2 =
                new S2LatLngRect(S2LatLng.FromDegrees(-15, 155), S2LatLng.FromDegrees(15, -155));

            assertTrue(llr1.ApproxEquals(llr2));

            llr1 = new S2LatLngRect(S2LatLng.FromDegrees(60, 150), S2LatLng.FromDegrees(80, 10))
                   .ConvolveWithCap(S1Angle.FromDegrees(15));
            llr2 = new S2LatLngRect(S2LatLng.FromDegrees(45, -180), S2LatLng.FromDegrees(90, 180));
            assertTrue(llr1.ApproxEquals(llr2));

            // GetCapBound(), bounding cap at center is smaller:
            assertTrue(new S2LatLngRect(S2LatLng.FromDegrees(-45, -45), S2LatLng.FromDegrees(45, 45)).CapBound.ApproxEquals(S2Cap.FromAxisHeight(new S2Point(1, 0, 0), 0.5)));
            // GetCapBound(), bounding cap at north pole is smaller:
            assertTrue(new S2LatLngRect(S2LatLng.FromDegrees(88, -80), S2LatLng.FromDegrees(89, 80)).CapBound.ApproxEquals(S2Cap.FromAxisAngle(new S2Point(0, 0, 1), S1Angle.FromDegrees(2))));
            // GetCapBound(), longitude span > 180 degrees:
            assertTrue(
                new S2LatLngRect(S2LatLng.FromDegrees(-30, -150), S2LatLng.FromDegrees(-10, 50)).CapBound
                .ApproxEquals(S2Cap.FromAxisAngle(new S2Point(0, 0, -1), S1Angle.FromDegrees(80))));

            // Contains(S2Cell), MayIntersect(S2Cell), Intersects(S2Cell)

            // Special cases.
            testCellOps(empty, S2Cell.FromFacePosLevel(3, (byte)0, 0), 0);
            testCellOps(full, S2Cell.FromFacePosLevel(2, (byte)0, 0), 4);
            testCellOps(full, S2Cell.FromFacePosLevel(5, (byte)0, 25), 4);

            // This rectangle includes the first quadrant of face 0. It's expanded
            // slightly because cell bounding rectangles are slightly conservative.
            var r4 = rectFromDegrees(-45.1, -45.1, 0.1, 0.1);

            testCellOps(r4, S2Cell.FromFacePosLevel(0, (byte)0, 0), 3);
            testCellOps(r4, S2Cell.FromFacePosLevel(0, (byte)0, 1), 4);
            testCellOps(r4, S2Cell.FromFacePosLevel(1, (byte)0, 1), 0);

            // This rectangle intersects the first quadrant of face 0.
            var r5 = rectFromDegrees(-10, -45, 10, 0);

            testCellOps(r5, S2Cell.FromFacePosLevel(0, (byte)0, 0), 3);
            testCellOps(r5, S2Cell.FromFacePosLevel(0, (byte)0, 1), 3);
            testCellOps(r5, S2Cell.FromFacePosLevel(1, (byte)0, 1), 0);

            // Rectangle consisting of a single point.
            testCellOps(rectFromDegrees(4, 4, 4, 4), S2Cell.FromFacePosLevel(0, (byte)0, 0), 3);

            // Rectangles that intersect the bounding rectangle of a face
            // but not the face itself.
            testCellOps(rectFromDegrees(41, -87, 42, -79), S2Cell.FromFacePosLevel(2, (byte)0, 0), 1);
            testCellOps(rectFromDegrees(-41, 160, -40, -160), S2Cell.FromFacePosLevel(5, (byte)0, 0), 1);
            {
                // This is the leaf cell at the top right hand corner of face 0.
                // It has two angles of 60 degrees and two of 120 degrees.
                var cell0tr  = new S2Cell(new S2Point(1 + 1e-12, 1, 1));
                var bound0tr = cell0tr.RectBound;
                var v0       = new S2LatLng(cell0tr.GetVertexRaw(0));
                testCellOps(
                    rectFromDegrees(v0.Lat.Degrees - 1e-8, v0.Lng.Degrees - 1e-8,
                                    v0.Lat.Degrees - 2e-10, v0.Lng.Degrees + 1e-10), cell0tr, 1);
            }

            // Rectangles that intersect a face but where no vertex of one region
            // is contained by the other region. The first one passes through
            // a corner of one of the face cells.
            testCellOps(rectFromDegrees(-37, -70, -36, -20), S2Cell.FromFacePosLevel(5, (byte)0, 0), 2);
            {
                // These two intersect like a diamond and a square.
                var cell202  = S2Cell.FromFacePosLevel(2, (byte)0, 2);
                var bound202 = cell202.RectBound;
                testCellOps(
                    rectFromDegrees(bound202.Lo.Lat.Degrees + 3, bound202.Lo.Lng.Degrees + 3,
                                    bound202.Hi.Lat.Degrees - 3, bound202.Hi.Lng.Degrees - 3), cell202, 2);
            }
        }