Test log2 function

test/spec/ol/math.test.js

@@ -2,6 +2,7 @@ import {
   clamp,
   cosh,
   lerp,
+  log2,
   modulo,
   solveLinearSystem,
   toDegrees,
@@ -52,6 +53,32 @@ describe('ol.math.cosh', function () {
   });
 });
 
+describe('ol.math.log2', function () {
+  it('returns the correct value at Infinity', function () {
+    expect(log2(Infinity)).to.eql(Infinity);
+  });
+
+  it('returns the correct value at 3', function () {
+    expect(log2(3)).to.roughlyEqual(1.584962500721156, 1e-9);
+  });
+
+  it('returns the correct value at 2', function () {
+    expect(log2(2)).to.eql(1);
+  });
+
+  it('returns the correct value at 1', function () {
+    expect(log2(1)).to.eql(0);
+  });
+
+  it('returns the correct value at 0', function () {
+    expect(log2(0)).to.eql(-Infinity);
+  });
+
+  it('returns the correct value at -1', function () {
+    expect(log2(0)).to.eql(NaN);
+  });
+});
+
 describe('ol.math.solveLinearSystem', function () {
   it('calculates correctly', function () {
     const result = solveLinearSystem([