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# JSAPI Test Suite
The tests in this directory exercise the JSAPI.
## Building and running the tests
If you built JS, you already built the tests.
The tests are built by default when you build JS. All the tests are compiled
into a single binary named jsapi-tests. They all run in a single process.
They must be run from the js/src directory.
To run the tests:
To run the tests in a debugger:
gdb $OBJDIR/dist/bin/jsapi-tests
## Creating new tests
1. You can either add to an existing test*.cpp file or make a new one.
Copy an existing test and replace the body with your test code.
The test harness provides `cx`, `rt`, and `global` for your use.
2. If you made a new .cpp file, add it to the UNIFIED_SOURCES list
## Writing test code
Here is a sample test:
#include "jsapi-tests/tests.h"
RootedValue v(cx);
EVAL("'42';", &v);
JSString *str = v.toString();
CHECK(JS_StringHasBeenInterned(cx, str));
CHECK(JS_FlatStringEqualsLiteral(JS_ASSERT_STRING_IS_FLAT(str), "42"));
return true;
The BEGIN_TEST and END_TEST macros bracket each test. By convention, the test
name is <testFilename>_<detail>. (The above test is in testIntString.cpp.)
The curly braces are required. This block is the body of a C++ member function
that returns bool. The test harness calls this member function
automatically. If the function returns true, the test passes. False, it fails.
JSAPI tests often need extra global C/C++ code: a JSClass, a getter or setter
function, a resolve hook. Put these before the BEGIN_TEST macro.
The body of the test can use these member variables and macros, defined in
JSRuntime *rt;
JSContext *cx;
JSObject *global;
The test framework creates these fresh for each test. The default
environment has reasonable default settings, including
JSOPTION_VAROBJFIX, JSOPTION_JIT, a global object of a class with
JSCLASS_GLOBAL_FLAGS, and an error reporter that prints to stderr.
See also "Custom test setup" below.
EXEC(const char *code);
Execute some JS code in global scope, using JS::Evaluate. Return
false if that fails. (This means that if the code throws an uncaught JS
exception, the test fails.)
EVAL(const char *code, jsval *vp);
Same as EXEC, but store the result value in *vp.
CHECK(bool cond);
If the condition is not true, print an error message and return false,
failing the test.
CHECK_SAME(jsval a, jsval b);
If a and b are different values, print an error message and return
false, failing the test.
This is like CHECK(sameValue(a, b)) but with a more detailed error
message on failure. See sameValue below.
CHECK_EQUAL(const T &a, const U &b);
CHECK(a == b), but with a more detailed error message.
CHECK_NULL(const T *ptr);
CHECK(ptr == nullptr), but with a more detailed error message.
(This is here because CHECK_EQUAL(ptr, nullptr) fails to compile on GCC
2.5 and before.)
bool knownFail;
Set this to true if your test is known to fail. The test runner will
print a TEST-KNOWN-FAIL line rather than a TEST-UNEXPECTED-FAIL
line. This way you can check in a test illustrating a bug ahead of the
If your test actually crashes the process or triggers an assertion,
this of course will not help, so you should add something like
knownFail = true; // see bug 123456
return false; // the code below crashes!
as the first two lines of the test.
bool isNegativeZero(jsval v);
bool isNaN(jsval v);
bool sameValue(jsval v1, jsval v2);
True if v1 and v2 are the same value according to the ES5 SameValue()
function, to wit:
SameValue(NaN, NaN) is true.
SameValue(-0, 0) is false.
Otherwise SameValue(a, b) iff a === b.
## Custom test setup
Before executing each test, the test framework calls the tests' init() member
function, which populates the rt, cx, and global member variables.
A test can customize the test setup process by overloading virtual member
functions from the JSAPIRuntimeTest class, like this:
const JSClass globalClassWithResolve = { ... };
RootedValue v;
EVAL("v", v.address());
return true;
// Other class members can go here.
// This one overloads a base-class method.
virtual JSClass *getGlobalJSClass() {
return &globalClassWithResolve;
The overloadable member functions are:
virtual bool init();
virtual void uninit();
virtual JSRuntime * createRuntime();
virtual JSContext * createContext();
virtual JSClass * getGlobalClass();
virtual JSObject * createGlobal();