Support \oiint and \oiiint (#1430)

* Support \oiint and \oiiint

* Fix sub. Add tests

* Add phony screenshots

* Add real screenshots

test/katex-spec.js

@@ -1350,6 +1350,23 @@ describe("A TeX-compliant parser", function() {
     });
 });
 
+describe("An op symbol builder", function() {
+    it("should not fail", function() {
+        expect("\\int_i^n").toBuild();
+        expect("\\iint_i^n").toBuild();
+        expect("\\iiint_i^n").toBuild();
+        expect("\\int\nolimits_i^n").toBuild();
+        expect("\\iint\nolimits_i^n").toBuild();
+        expect("\\iiint\nolimits_i^n").toBuild();
+        expect("\\oint_i^n").toBuild();
+        expect("\\oiint_i^n").toBuild();
+        expect("\\oiiint_i^n").toBuild();
+        expect("\\oint\nolimits_i^n").toBuild();
+        expect("\\oiint\nolimits_i^n").toBuild();
+        expect("\\oiiint\nolimits_i^n").toBuild();
+    });
+});
+
 describe("A style change parser", function() {
     it("should not fail", function() {
         expect("\\displaystyle x").toParse();

test/screenshotter/ss_data.yaml

@@ -132,6 +132,12 @@ GroupMacros:
         \endExp: \egroup
     tex: \startExp a+b\endExp
 HorizontalBraces: \overbrace{\displaystyle{\oint_S{\vec E\cdot\hat n\,\mathrm d a}}}^\text{emf} = \underbrace{\frac{q_{\text{enc}}}{\varepsilon_0}}_{\text{charge}}
+Integrands: |
+    \begin{array}{l}
+        \displaystyle \int + \oint + \iint + \oiint_i^n \\[0.6em]
+        \displaystyle \iiint + \oiiint + \textstyle \int + \oint_i^n \\[0.6em]
+        \iint + \oiint + \iiint + \oiiint
+    \end{array}
 KaTeX:
     tex: \KaTeX
     nolatex: \KaTeX not supported by LaTeX