Feature random position

lib/random_position.dart

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+library turf_random_position;
+
+export 'src/random_position.dart';
+export 'package:geotypes/geotypes.dart';

lib/src/random_position.dart

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+import 'dart:math';
+
+import 'package:turf/turf.dart';
+
+// Returns a random Position within a Bbox
+// Dart Random function module is obtained from dart:math
+
+Position randomPosition(BBox? bbox) {
+  checkBBox(bbox);
+  return randomPositionUnchecked(bbox);
+}
+
+// Returns a Random Position without checking if it is valid
+Position randomPositionUnchecked(BBox? bbox) {
+  return coordInBBox(bbox);
+}
+
+// Performs checks on bbox ensuring a bbox is provided, and contains 4 values.
+void checkBBox(BBox? bbox) {
+  if (bbox == null) {
+    throw ArgumentError("Bbox cannot be null.");
+  }
+  if (bbox.length != 4) {
+    throw ArgumentError("Bbox must contain exactly 4 values.");
+  }
+}
+
+// Returns a random Position within bbox
+Position coordInBBox(BBox? bbox) {
+  if (bbox == null) {
+    throw ArgumentError("Bbox cannot be null.");
+  }
+  return Position(bbox[0]! + Random().nextDouble() * (bbox[2]! - bbox[0]!),
+      bbox[1]! + Random().nextDouble() * (bbox[3]! - bbox[1]!));
+}

test/components/random_position_test.dart

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+import 'package:turf/random_position.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('Random Position tests', () {
+    test('Generating a random position within a bounding box', () {
+      BBox bbox = BBox(100.0, -24.0, 110.0, -23.0);
+      Position randomPos = randomPosition(bbox);
+
+      expect(randomPos.lng, greaterThanOrEqualTo(bbox[0]!));
+      expect(randomPos.lng, lessThanOrEqualTo(bbox[2]!));
+      expect(randomPos.lat, greaterThanOrEqualTo(bbox[1]!));
+      expect(randomPos.lat, lessThanOrEqualTo(bbox[3]!));
+    });
+
+    test('Check coordInBox returns point within bbox', () {
+      BBox bbox = BBox(100.0, -24.0, 110.0, -23.0);
+      Position coord = coordInBBox(bbox);
+      expect(coord.lng, greaterThanOrEqualTo(bbox[0]!));
+      expect(coord.lng, lessThanOrEqualTo(bbox[2]!));
+      expect(coord.lat, greaterThanOrEqualTo(bbox[1]!));
+      expect(coord.lat, lessThanOrEqualTo(bbox[3]!));
+    });
+  });
+}