Merge pull request #423 from Khan/kern

Add support for \kern

test/katex-spec.js

@@ -910,6 +910,31 @@ describe("A rule parser", function() {
     });
 });
 
+describe("A kern parser", function() {
+    var emKern = "\\kern{1em}";
+    var exKern = "\\kern{1ex}";
+    var badUnitRule = "\\kern{1px}";
+    var noNumberRule = "\\kern{em}";
+
+    it("should list the correct units", function() {
+        var emParse = getParsed(emKern)[0];
+        var exParse = getParsed(exKern)[0];
+
+        expect(emParse.value.dimension.unit).toEqual("em");
+        expect(exParse.value.dimension.unit).toEqual("ex");
+    });
+
+    it("should not parse invalid units", function() {
+        expect(badUnitRule).toNotParse();
+        expect(noNumberRule).toNotParse();
+    });
+
+    it("should parse negative sizes", function() {
+        var parse = getParsed("\\kern{-1em}")[0];
+        expect(parse.value.dimension.number).toBeCloseTo(-1);
+    });
+});
+
 describe("A left/right parser", function() {
     var normalLeftRight = "\\left( \\dfrac{x}{y} \\right)";
     var emptyRight = "\\left( \\dfrac{x}{y} \\right.";