Grand test fixup (#138)

* start fixing up tests

* fix up tests + automate with drone

* fiddle with linting

* messing about with drone.yml

* some more fiddling

* hmmm

* add cache

* add vendor directory

* verbose

* ci updates

* update some little things

* update sig

vendor/github.com/golang/geo/s2/region.go

@@ -0,0 +1,71 @@
+// Copyright 2014 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package s2
+
+// A Region represents a two-dimensional region on the unit sphere.
+//
+// The purpose of this interface is to allow complex regions to be
+// approximated as simpler regions. The interface is restricted to methods
+// that are useful for computing approximations.
+type Region interface {
+	// CapBound returns a bounding spherical cap. This is not guaranteed to be exact.
+	CapBound() Cap
+
+	// RectBound returns a bounding latitude-longitude rectangle that contains
+	// the region. The bounds are not guaranteed to be tight.
+	RectBound() Rect
+
+	// ContainsCell reports whether the region completely contains the given region.
+	// It returns false if containment could not be determined.
+	ContainsCell(c Cell) bool
+
+	// IntersectsCell reports whether the region intersects the given cell or
+	// if intersection could not be determined. It returns false if the region
+	// does not intersect.
+	IntersectsCell(c Cell) bool
+
+	// ContainsPoint reports whether the region contains the given point or not.
+	// The point should be unit length, although some implementations may relax
+	// this restriction.
+	ContainsPoint(p Point) bool
+
+	// CellUnionBound returns a small collection of CellIDs whose union covers
+	// the region. The cells are not sorted, may have redundancies (such as cells
+	// that contain other cells), and may cover much more area than necessary.
+	//
+	// This method is not intended for direct use by client code. Clients
+	// should typically use Covering, which has options to control the size and
+	// accuracy of the covering. Alternatively, if you want a fast covering and
+	// don't care about accuracy, consider calling FastCovering (which returns a
+	// cleaned-up version of the covering computed by this method).
+	//
+	// CellUnionBound implementations should attempt to return a small
+	// covering (ideally 4 cells or fewer) that covers the region and can be
+	// computed quickly. The result is used by RegionCoverer as a starting
+	// point for further refinement.
+	CellUnionBound() []CellID
+}
+
+// Enforce Region interface satisfaction.
+var (
+	_ Region = Cap{}
+	_ Region = Cell{}
+	_ Region = (*CellUnion)(nil)
+	_ Region = (*Loop)(nil)
+	_ Region = Point{}
+	_ Region = (*Polygon)(nil)
+	_ Region = (*Polyline)(nil)
+	_ Region = Rect{}
+)