Commit Graph

1783 Commits

Author SHA1 Message Date
Yonatan Goldschmidt 35e664d779 tests/unix: Add coverage tests for mp_obj_is_type() and variants. 2020-01-24 10:57:17 +11:00
Damien George 27f41e624c tests/unix: Add coverage test for mp_obj_new_exception_args.
Because it's no longer called anywhere in the code.
2020-01-23 13:37:25 +11:00
Damien George dccace6f3f tests/unix: Add coverage tests for pairheap data structure. 2020-01-22 17:31:18 +11:00
Damien George cfddc6a8c7 tests/extmod: Add basic machine.Timer test. 2020-01-22 17:31:18 +11:00
Thorsten von Eicken 5c5f93c1b8 tests: Make run-tests help and README be more descriptive of behaviour. 2020-01-22 16:35:24 +11:00
Damien George 3448e69c2d tests/unix: Add coverage test for new mp_obj_int_get_uint_checked func. 2020-01-14 23:45:56 +11:00
Yonatan Goldschmidt 853aaa06f2 lib/mp-readline: Add word-based move/delete EMACS key sequences.
This commit adds backward-word, backward-kill-word, forward-word,
forward-kill-word sequences for the REPL, with bindings to Alt+F, Alt+B,
Alt+D and Alt+Backspace respectively.  It is disabled by default and can be
enabled via MICROPY_REPL_EMACS_WORDS_MOVE.

Further enabling MICROPY_REPL_EMACS_EXTRA_WORDS_MOVE adds extra bindings
for these new sequences: Ctrl+Right, Ctrl+Left and Ctrl+W.

The features are enabled on unix micropython-coverage and micropython-dev.
2020-01-12 13:09:27 +11:00
Jim Mussared 977b532c8f unix: Rename unix binaries to micropython-variant (not _variant).
For consistency with mpy-cross, and other unix tools in general.
2020-01-12 10:37:40 +11:00
stijn 54a2584de1 tests/unix: Make unix time test pass on more platforms.
As the mktime documentation for CPython states: "The earliest date for
which it can generate a time is platform-dependent".  In particular on
Windows this depends on the timezone so e.g. for UTC+2 the earliest is 2
hours past midnight January 1970.  So change the reference to the earliest
possible, for UTC+14.
2020-01-06 23:28:42 +11:00
Damien George 4d528bbaa8 tests/cpydiff: Add CPy diff-test for using dict.keys() as a set.
See issue #5493.
2020-01-06 23:26:00 +11:00
David Lechner 1bc9fc8082 tests/run-tests: Handle 'CRASH' return by float.py feature test.
It is possile for `run_feature_check(pyb, args, base_path, 'float.py')` to
return `b'CRASH'`.  This causes an unhandled exception in `int()`.

This commit fixes the problem by first testing for `b'CRASH'` before trying
to convert the return value to an integer.
2020-01-06 22:22:27 +11:00
Nicko van Someren 4c93955b7b py/objslice: Add support for indices() method on slice objects.
Instances of the slice class are passed to __getitem__() on objects when
the user indexes them with a slice.  In practice the majority of the time
(other than passing it on untouched) is to work out what the slice means in
the context of an array dimension of a particular length.  Since Python 2.3
there has been a method on the slice class, indices(), that takes a
dimension length and returns the real start, stop and step, accounting for
missing or negative values in the slice spec.  This commit implements such
a indices() method on the slice class.

It is configurable at compile-time via MICROPY_PY_BUILTINS_SLICE_INDICES,
disabled by default, enabled on unix, stm32 and esp32 ports.

This commit also adds new tests for slice indices and for slicing unicode
strings.
2019-12-28 23:55:15 +11:00
Andrew Leech 1b844e908c unix/modtime: Add utime.mktime function, to complement utime.localtime.
This also adds it to the windows port.
2019-12-28 11:11:54 +11:00
Damien George f5eec903fa py/objsingleton: Use mp_generic_unary_op for singleton objects.
So these types more closely match NoneType, eg they can be hashed, like in
CPython.
2019-12-27 12:53:36 +11:00
Damien George de8c04317b tests/micropython: Add test for yield-from while heap is locked. 2019-12-27 12:34:22 +11:00
Damien George 99a04b8060 tests/extmod: Split out VfsFat finaliser tests to separate test file.
It tests independent functionality and may need to be skipped for a given
port.
2019-12-27 12:30:51 +11:00
Damien George 865827ed8e tests/run-tests: Add "--mpy-cross-flags" arg to specify mpy-cross flags. 2019-12-27 12:30:51 +11:00
Yonatan Goldschmidt 42e45bd694 py/objobject: Add object.__delattr__ function.
Similar to object.__setattr__.
2019-12-21 00:14:22 +11:00
Yonatan Goldschmidt 07ccb5588c py/objobject: Add object.__setattr__ function.
Allows assigning attributes on class instances that implement their own
__setattr__.  Both object.__setattr__ and super(A, b).__setattr__ will work
with this commit.
2019-12-21 00:12:08 +11:00
Damien George 39bc430e44 tests/pyb: Adjust UART and Timer tests to work on PYBD_SF6. 2019-12-20 16:42:38 +11:00
Damien George 4b184d1281 tests/pyb: Refactor pyboard tests to work on PYBv1, PYBLITEv1 and PYBD. 2019-12-13 17:27:29 +11:00
Damien George 7280bf40d9 tests/extmod/vfs_lfs_error: Use small ints in seek error test.
So accessing the seek offset (at the C level) doesn't cause an
OverflowError on 32-bit targets.
2019-12-13 15:59:08 +11:00
Damien George 1098d1d630 tests/basics/memoryview_itemsize: Make portable to 32- and 64-bit archs. 2019-12-13 15:59:08 +11:00
Damien George 33b0a7e601 tests/stress/qstr_limit: Tune params to run with stm32 port.
Because MICROPY_ALLOC_PATH_MAX is only 128 for this port.
2019-12-13 15:58:28 +11:00
Damien George 624f4ca39b tests: Add .exp files for basics/parser and import/import_override.
Because CPython 3.8.0 now produces different output:
- basics/parser.py: CPython does not allow '\\\n' as input.
- import/import_override: CPython imports _io.
2019-12-13 14:20:47 +11:00
Damien George ba84453f77 examples/natmod: Add urandom native module example. 2019-12-13 13:33:40 +11:00
Damien George 4eef940edb tests: Add script to run dynamic-native-module tests. 2019-12-12 20:15:28 +11:00
Damien George 111d1ffb64 tests/import: Add test for importing viper code with additional flags. 2019-12-12 20:15:28 +11:00
Damien George 1675b98e74 tests/stress: Add test for maximum length limit of qstrs. 2019-11-26 13:15:00 +11:00
Léa Saviot a7bc4d1a14 py/builtinimport: Raise exception on empty module name.
To prevent a crash returning MP_OBJ_NULL.  A test is added for this case.
2019-11-26 00:28:32 +11:00
Andrew Leech 1e87f11d3f py/objdict: Support ujson.dump() of OrderedDict objects.
Following CPython, OrderedDict are dumped with the syntax of dict.
2019-11-13 13:51:18 +11:00
Damien George 80df377e95 py/modsys: Report .mpy version in sys.implementation.
This commit adds a sys.implementation.mpy entry when the system supports
importing .mpy files.  This entry is a 16-bit integer which encodes two
bytes of information from the header of .mpy files that are supported by
the system being run: the second and third bytes, .mpy version, and flags
and native architecture.  This allows determining the supported .mpy file
dynamically by code, and also for the user to find it out by inspecting
this value.  It's further possible to dynamically detect if the system
supports importing .mpy files by `hasattr(sys.implementation, 'mpy')`.
2019-11-04 16:00:41 +11:00
Jim Mussared 5578182ec9 py/objgenerator: Allow pend_throw to an unstarted generator.
Replace the is_running field with a tri-state variable to indicate
running/not-running/pending-exception.

Update tests to cover the various cases.

This allows cancellation in uasyncio even if the coroutine hasn't been
executed yet.  Fixes #5242
2019-11-04 15:51:16 +11:00
Damien George 43f53a2bbd tests/extmod: Add test for ussl when passing in key/cert params. 2019-10-31 16:38:20 +11:00
Damien George feaa251674 extmod/modlwip: Make socket poll return POLLNVAL in case of bad file. 2019-10-31 12:54:37 +11:00
Damien George 71401d5065 extmod/modlwip: Unconditionally return POLLHUP when polling new socket.
POSIX poll should always return POLLERR and POLLHUP in revents, regardless
of whether they were requested in the input events flags.

See issues #4290 and #5172.
2019-10-31 12:54:37 +11:00
Damien George 9ec73aedb4 stm32/timer: Fix Timer.freq() calc so mult doesn't overflow uint32_t.
Fixes issue #5280.
2019-10-31 12:49:18 +11:00
Damien George 943dd33b5f tests/basics: Split sys.exit test to separate file so it can be skipped. 2019-10-29 22:22:37 +11:00
Damien George 1d51115246 tests: Add feature check for uio module and skip corresponding tests. 2019-10-29 22:22:37 +11:00
Damien George eebffb2b5b tests/basics: Automatically skip tests that use str/bytes modulo-format. 2019-10-29 22:22:37 +11:00
Damien George 52299ed3f0 tests/run-tests: Add misc list of tests that use slice, to skip them. 2019-10-29 22:22:37 +11:00
Damien George b5186c9271 tests/basics: Split out specific slice tests to separate files.
So they can be automatically skipped if slice is not enabled.
2019-10-29 22:22:37 +11:00
Damien George ecb77e40e0 tests: Add feature check for slice and skip corresponding tests. 2019-10-29 22:22:37 +11:00
Damien George 9162a87d4d tests/basics: Use bytes not bytearray when checking user buffer proto.
Using bytes will test the same path for the buffer protocol in
py/objtype.c.
2019-10-29 22:22:37 +11:00
Damien George aeea204e98 tests/basics: Split out specific bytearray tests to separate files.
So they can be automatically skipped if bytearray is not enabled.
2019-10-29 22:22:37 +11:00
Damien George 6e9ba1cf4b tests: Add feature check for bytearray and skip corresponding tests. 2019-10-29 22:22:37 +11:00
Damien George 7a49fc387c tests/basics/builtin_dir.py: Look for "version" in dir(sys).
Because "version" will always be there, but "exit" may not.
2019-10-29 22:22:37 +11:00
Damien George 709136e844 tests/basics: Use str.format instead of % for formatting messages.
Only use % formatting when testing % itself, because only str.format is
guaranteed to be available on any port.
2019-10-29 22:22:37 +11:00
Damien George cfe1c5abf8 extmod/vfs: Rename BP_IOCTL_xxx constants to MP_BLOCKDEV_IOCTL_xxx.
Also rename SEC_COUNT to BLOCK_COUNT and SEC_SIZE to BLOCK_SIZE.
2019-10-29 14:17:29 +11:00
Damien George 7c8fb27f38 tests/extmod: Add test for blockdev with standard and extended protocol. 2019-10-29 14:17:29 +11:00
Damien George 73fddb84e5 tests/extmod: Add littlefs tests. 2019-10-29 14:17:29 +11:00
Damien George 30e25174bb tests: Rename "array" module to "uarray". 2019-10-22 19:16:54 +11:00
clach04 ffd11486d4 tests/cpydiff: Fix typo in types_bytes_keywords.py doc comments. 2019-10-21 23:25:09 +11:00
Josh Lloyd 8f9e2e325a py/objtype: Add type.__bases__ attribute.
Enabled as part of MICROPY_CPYTHON_COMPAT.
2019-10-18 15:20:56 +11:00
Jim Mussared ebf8332104 extmod/re1.5: Support escaping within RE classes.
Fixes issues #3178 and #5220.

Tests are added, including all the cases mentioned in both bugs.
2019-10-18 12:20:32 +11:00
Damien George 23f0691fdd py/persistentcode: Make .mpy more compact with qstr directly in prelude.
Instead of encoding 4 zero bytes as placeholders for the simple_name and
source_file qstrs, and storing the qstrs after the bytecode, store the
qstrs at the location of these 4 bytes.  This saves 4 bytes per bytecode
function stored in a .mpy file (for example lcd160cr.mpy drops by 232
bytes, 4x 58 functions).  And resulting code size is slightly reduced on
ports that use this feature.
2019-10-15 16:56:27 +11:00
Damien George 858e992d2e tests/run-perfbench.py: Skip complex tests if target doesn't enable it. 2019-10-15 16:46:06 +11:00
Jim Mussared f1882636c0 tests/run-perfbench.py: Show error when truth check fails. 2019-10-15 16:38:11 +11:00
Jim Mussared cfd17f4ebe tests/perf_bench: Add bm_fft test.
This is mostly a test of complex number performance.

The FFT implementation is from Project Nayuki and is MIT licensed.
2019-10-15 16:38:11 +11:00
Damien George 27fe84e661 tests/basics: Add test for throw into yield-from with normal return.
This test was found by missing coverage of a branch in py/nativeglue.c.
2019-10-04 23:27:48 +10:00
Damien George 809d89c794 py/runtime: Fix PEP479 behaviour throwing StopIteration into yield from.
Commit 3f6ffe059f implemented PEP479 but did
not catch the case fixed in this commit.  Found by coverage analysis, that
the VM had uncovered code.
2019-10-04 23:27:00 +10:00
Damien George 82c494a97e py/vm: Fix handling of unwind jump out of active finally.
Prior to this commit, when unwinding through an active finally the stack
was not being correctly popped/folded, which resulting in the VM crashing
for complicated unwinding of nested finallys.

This should be fixed with this commit, and more tests for return/break/
continue within a finally have been added to exercise this.
2019-10-04 23:01:29 +10:00
Petr Viktorin 25a9bccdee py/compile: Disallow 'import *' outside module level.
This check follows CPython's behaviour, because 'import *' always populates
the globals with the imported names, not locals.

Since it's safe to do this (doesn't lead to a crash or undefined behaviour)
the check is only enabled for MICROPY_CPYTHON_COMPAT.

Fixes issue #5121.
2019-10-04 16:46:47 +10:00
Damien George 4102320e90 tests/basics: Add test for getting name of func with closed over locals.
Tests correct decoding of the prelude to get the function name.
2019-10-01 12:26:22 +10:00
Damien George c8c0fd4ca3 py: Rework and compress second part of bytecode prelude.
This patch compresses the second part of the bytecode prelude which
contains the source file name, function name, source-line-number mapping
and cell closure information.  This part of the prelude now begins with a
single varible length unsigned integer which encodes 2 numbers, being the
byte-size of the following 2 sections in the header: the "source info
section" and the "closure section".  After decoding this variable unsigned
integer it's possible to skip over one or both of these sections very
easily.

This scheme saves about 2 bytes for most functions compared to the original
format: one in the case that there are no closure cells, and one because
padding was eliminated.
2019-10-01 12:26:22 +10:00
Damien George b5ebfadbd6 py: Compress first part of bytecode prelude.
The start of the bytecode prelude contains 6 numbers telling the amount of
stack needed for the Python values and exceptions, and the signature of the
function.  Prior to this patch these numbers were all encoded one after the
other (2x variable unsigned integers, then 4x bytes), but using so many
bytes is unnecessary.

An entropy analysis of around 150,000 bytecode functions from the CPython
standard library showed that the optimal Shannon coding would need about
7.1 bits on average to encode these 6 numbers, compared to the existing 48
bits.

This patch attempts to get close to this optimal value by packing the 6
numbers into a single, varible-length unsigned integer via bit-wise
interleaving.  The interleaving scheme is chosen to minimise the average
number of bytes needed, and at the same time keep the scheme simple enough
so it can be implemented without too much overhead in code size or speed.
The scheme requires about 10.5 bits on average to store the 6 numbers.

As a result most functions which originally took 6 bytes to encode these 6
numbers now need only 1 byte (in 80% of cases).
2019-10-01 12:26:22 +10:00
Jim Mussared f67fd95f8d unix/coverage: Add coverage tests for ringbuf. 2019-10-01 09:51:02 +10:00
Damien George 095f90f04e tests/micropython: Add test for native generators. 2019-09-26 16:53:47 +10:00
Damien George 5716c5cf65 py/persistentcode: Bump .mpy version to 5.
The bytecode opcodes have changed (there are more, and they have been
reordered).
2019-09-26 16:39:37 +10:00
Josh Lloyd 7d58a197cf py: Rename MP_QSTR_NULL to MP_QSTRnull to avoid intern collisions.
Fixes #5140.
2019-09-26 16:04:56 +10:00
Damien George 02db91a7a3 py: Split RAISE_VARARGS opcode into 3 separate ones.
From the beginning of this project the RAISE_VARARGS opcode was named and
implemented following CPython, where it has an argument (to the opcode)
counting how many args the raise takes:

    raise # 0 args (re-raise previous exception)
    raise exc # 1 arg
    raise exc from exc2 # 2 args (chained raise)

In the bytecode this operation therefore takes 2 bytes, one for
RAISE_VARARGS and one for the number of args.

This patch splits this opcode into 3, where each is now a single byte.
This reduces bytecode size by 1 byte for each use of raise.  Every byte
counts!  It also has the benefit of reducing code size (on all ports except
nanbox).
2019-09-26 15:39:50 +10:00
Damien George 67fdfebe64 tests: Update tests for changes to opcode ordering. 2019-09-26 15:27:11 +10:00
Damien George fe4e1fe4b9 tests/basics: Add test for matmul operator.
This is a Python 3.5 feature so the .exp file is needed.
2019-09-26 15:15:34 +10:00
Damien George 2069c563f9 py: Add support for matmul operator @ as per PEP 465.
To make progress towards MicroPython supporting Python 3.5, adding the
matmul operator is important because it's a really "low level" part of the
language, being a new token and modifications to the grammar.

It doesn't make sense to make it configurable because 1) it would make the
grammar and lexer complicated/messy; 2) no other operators are
configurable; 3) it's not a feature that can be "dynamically plugged in"
via an import.

And matmul can be useful as a general purpose user-defined operator, it
doesn't have to be just for numpy use.

Based on work done by Jim Mussared.
2019-09-26 15:12:39 +10:00
Damien George b29fae0c56 py/bc: Fix size calculation of UNWIND_JUMP opcode in mp_opcode_format.
Prior to this patch mp_opcode_format would calculate the incorrect size of
the MP_BC_UNWIND_JUMP opcode, missing the additional byte.  But, because
opcodes below 0x10 are unused and treated as bytes in the .mpy load/save
and freezing code, this bug did not show any symptoms, since nested unwind
jumps would rarely (if ever) reach a depth of 16 (so the extra byte of this
opcode would be between 0x01 and 0x0f and be correctly loaded/saved/frozen
simply as an undefined opcode).

This patch fixes this bug by correctly accounting for the additional byte.
        .
2019-09-02 13:30:16 +10:00
Damien George 24c3e9b283 py/modstruct: Fix struct.pack_into with unaligned offset of native type.
Following the same fix for unpack.
2019-09-02 13:14:16 +10:00
Tom McDermott 1022f9cc35 py/modstruct: Fix struct.unpack with unaligned offset of native type.
With this patch alignment is done relative to the start of the buffer that
is being unpacked, not the raw pointer value, as per CPython.

Fixes issue #3314.
2019-09-02 13:10:55 +10:00
Milan Rossa 498e35219e tests: Add tests for sys.settrace feature. 2019-08-30 16:48:22 +10:00
Damien George b3152b2de7 tests: Split out test for optimisation level and line-no printing. 2019-08-28 12:47:58 +10:00
Damien George 08c1fe5569 py/vm: Don't add traceback info for exceptions that are re-raised.
With this patch exceptions that are re-raised have improved tracebacks
(less confusing, match CPython), and it makes re-raise slightly more
efficient (in time and RAM) because they no longer need to add a traceback.
Also general VM performance is not measurably affected.

Partially fixes issue #2928.
2019-08-28 12:31:53 +10:00
Damien George 16f6169c88 py/vm: Don't add traceback info for exc's propagated through a finally.
With this patch exception tracebacks that go through a finally are improved
(less confusing, match CPython), and it makes finally's slightly more
efficient (in time and RAM) because they no longer need to add a traceback.

Partially fixes issue #2928.
2019-08-28 12:31:49 +10:00
Damien George 2eb88f5df7 tests/extmod: Split json.loads of bytes/bytearray into separate test.
Because this functionality was introduced in Python 3.6.
2019-08-22 15:45:13 +10:00
Damien George 2dfa69efbb extmod/modujson: Support passing bytes/bytearray to json.loads.
CPython allows this, and it can be useful to reduce the number of memory
allocations.

Fixes issue #5031.
2019-08-22 15:32:26 +10:00
Jim Mussared 0bd1eb80ff qemu-arm: Add testing of frozen native modules.
- Split 'qemu-arm' from 'unix' for generating tests.
- Add frozen module to the qemu-arm test build.
- Add test that reproduces the requirement to half-word align native
  function data.
2019-08-20 15:14:08 +10:00
Milan Rossa ae6fe8b43c py/compile: Improve the line numbering precision for comprehensions.
The line number for comprehensions is now always reported as the correct
global location in the script, instead of just "line 1".
2019-08-19 23:50:30 +10:00
Damien George 7d851a27f1 extmod/modure: Make regex dump-code debugging feature optional.
Enabled via MICROPY_PY_URE_DEBUG, disabled by default (but enabled on unix
coverage build).  This is a rarely used feature that costs a lot of code
(500-800 bytes flash).  Debugging of regular expressions can be done
offline with other tools.
2019-08-19 16:43:00 +10:00
stijn af5c998f37 py/modmath: Implement math.isclose() for non-complex numbers.
As per PEP 485, this function appeared in for Python 3.5.  Configured via
MICROPY_PY_MATH_ISCLOSE which is disabled by default, but enabled for the
ports which already have MICROPY_PY_MATH_SPECIAL_FUNCTIONS enabled.
2019-08-17 23:23:17 +10:00
Damien George acfbb9febd py/objarray: Fix amount of free space in array when doing slice assign.
Prior to this patch the amount of free space in an array (including
bytearray) was not being maintained correctly for the case of slice
assignment which changed the size of the array.  Under certain cases (as
encoded in the new test) it was possible that the array could grow beyond
its allocated memory block and corrupt the heap.

Fixes issue #4127.
2019-08-15 23:02:04 +10:00
Damien George 64abc1f47a tests/unix: Update extra_coverage expected output with new atexit func. 2019-08-15 18:56:01 +10:00
Milan Rossa 28cb15d131 tests/misc/sys_atexit: Add test for new sys.atexit feature. 2019-08-15 17:31:04 +10:00
Damien George cd35dd9d9a py: Allow to pass in read-only buffers to viper and inline-asm funcs.
Fixes #4936.
2019-08-06 15:58:23 +10:00
Damien George 48f43b77aa tests: Add tests for overriding builtins.__import__. 2019-07-31 22:37:44 +10:00
Paul m. p. P a8e3201b37 py/builtinimport: Populate __file__ when importing frozen or mpy files.
Note that bytecode already includes the source filename as a qstr so there
is no additional memory used by the interning operation here.
2019-07-31 17:00:11 +10:00
Eric Poulsen 01054f2092 py/objdict: Quote non-string types when used as keys in JSON output.
JSON requires that keys of objects be strings.  CPython will therefore
automatically quote simple types (NoneType, bool, int, float) when they are
used directly as keys in JSON output.  To prevent subtle bugs and emit
compliant JSON, MicroPython should at least test for such keys so they
aren't silently let through.  Then doing the actual quoting is a similar
cost to raising an exception, so that's what is implemented by this patch.

Fixes issue #4790.
2019-07-30 16:34:27 +10:00
Damien George 3967dd68e8 tests/run-perfbench.py: Add --emit option to select emitter for tests. 2019-07-19 14:07:41 +10:00
Damien George 3e55830066 tests/stress/recursive_iternext.py: Increase large depth to 5000.
So it fails correctly on Linux with clang.
2019-07-17 15:52:41 +10:00
Damien George 73fccf5967 tests/perf_bench: Add some viper performance benchmarks.
To test raw viper function call overhead: function entry, exit and
conversion of arguments to/from objects.
2019-06-28 16:30:01 +10:00
Damien George 73c269414f tests/perf_bench: Add some miscellaneous performance benchmarks.
misc_aes.py and misc_mandel.py are adapted from sources in this repository.
misc_pystone.py is the standard Python pystone test.  misc_raytrace.py is
written from scratch.
2019-06-28 16:29:23 +10:00
Damien George 127714c3af tests/perf_bench: Add some benchmarks from python-performance.
From https://github.com/python/pyperformance commit
6690642ddeda46fc5ee6e97c3ef4b2f292348ab8
2019-06-28 16:29:23 +10:00
Damien George e92c9aa9c9 tests: Add performance benchmarking test-suite framework.
This benchmarking test suite is intended to be run on any MicroPython
target.  As such all tests are parameterised with N and M: N is the
approximate CPU frequency (in MHz) of the target and M is the approximate
amount of heap memory (in kbytes) available on the target.  When running
the benchmark suite these parameters must be specified and then each test
is tuned to run on that target in a reasonable time (<1 second).

The test scripts are not standalone: they require adding some extra code at
the end to run the test with the appropriate parameters.  This is done
automatically by the run-perfbench.py script, in such a way that imports
are minimised (so the tests can be run on targets without filesystem
support).

To interface with the benchmarking framework, each test provides a
bm_params dict and a bm_setup function, with the later taking a set of
parameters (chosen based on N, M) and returning a pair of functions, one to
run the test and one to get the results.

When running the test the number of microseconds taken by the test are
recorded.  Then this is converted into a benchmark score by inverting it
(so higher number is faster) and normalising it with an appropriate factor
(based roughly on the amount of work done by the test, eg number of
iterations).

Test outputs are also compared against a "truth" value, computed by running
the test with CPython.  This provides a basic way of making sure the test
actually ran correctly.

Each test is run multiple times and the results averaged and standard
deviation computed.  This is output as a summary of the test.

To make comparisons of performance across different runs the
run-perfbench.py script also includes a diff mode that reads in the output
of two previous runs and computes the difference in performance.  Reports
are given as a percentage change in performance with a combined standard
deviation to give an indication if the noise in the benchmarking is less
than the thing that is being measured.

Example invocations for PC, pyboard and esp8266 targets respectively:

    $ ./run-perfbench.py 1000 1000
    $ ./run-perfbench.py --pyboard 100 100
    $ ./run-perfbench.py --pyboard --device /dev/ttyUSB0 50 25
2019-06-28 16:29:23 +10:00