add test for locateFile

Author: kripken

tests/test_browser.py

@@ -1992,3 +1992,34 @@ def test_wget(self):
     with open(os.path.join(self.get_dir(), 'test.txt'), 'w') as f:
       f.write('emscripten')
     self.btest(path_from_root('tests', 'test_wget.c'), expected='1', args=['-s', 'ASYNCIFY=1'])
+
+  def test_locate_file(self):
+    self.clear()
+    open('src.cpp', 'w').write(self.with_report_result(r'''
+      #include <stdio.h>
+      #include <string.h>
+      #include <assert.h>
+      int main() {
+        FILE *f = fopen("data.txt", "r");
+        assert(f && "could not open file");
+        char buf[100];
+        int num = fread(buf, 1, 20, f);
+        assert(num == 20 && "could not read 20 bytes");
+        buf[20] = 0;
+        fclose(f);
+        int result = !strcmp("load me right before", buf);
+        printf("|%s| : %d\n", buf, result);
+        REPORT_RESULT();
+        return 0;
+      }
+    '''))
+    open('data.txt', 'w').write('load me right before...')
+    open('pre.js', 'w').write('Module.locateFile = function(x) { return "sub/" + x };')
+    Popen([PYTHON, FILE_PACKAGER, 'test.data', '--preload', 'data.txt'], stdout=open('data.js', 'w')).communicate()
+    # put pre.js first, then the file packager data, so locateFile is there for the file loading code
+    Popen([PYTHON, EMCC, 'src.cpp', '-O2', '-g', '--pre-js', 'pre.js', '--pre-js', 'data.js', '-o', 'page.html']).communicate()
+    os.mkdir('sub')
+    shutil.move('page.html.mem', os.path.join('sub', 'page.html.mem'))
+    shutil.move('test.data', os.path.join('sub', 'test.data'))
+    self.run_browser('page.html', None, '/report_result?1')
+