test/test_buffer.cpp@67e078518935
test/test_buffer.cpp
Sun, 01 May 2022 11:44:23 +0200
- author
- Mike Becker <universe@uap-core.de>
- date
- Sun, 01 May 2022 11:44:23 +0200
- changeset 541
- 67e078518935
- parent 539
- 9cd98da9ee17
- child 542
- 45bcfd152f85
- permissions
- -rw-r--r--
#170 complete write tests for status quo
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
29 #include "cx/buffer.h"
31 #include <gtest/gtest.h>
32 #include "util_allocator.h"
34 static void expect_default_flush_config(CxBuffer *buf) {
35 EXPECT_EQ(buf->flush_blkmax, 0);
36 EXPECT_EQ(buf->flush_blksize, 4096);
37 EXPECT_EQ(buf->flush_threshold, SIZE_MAX);
38 EXPECT_EQ(buf->flush_func, nullptr);
39 EXPECT_EQ(buf->flush_target, nullptr);
40 }
42 TEST(BufferInit, WrapSpace) {
43 CxTestingAllocator alloc;
44 CxBuffer buf;
45 void *space = cxMalloc(&alloc, 16);
46 cxBufferInit(&buf, space, 16, &alloc, CX_BUFFER_DEFAULT);
47 expect_default_flush_config(&buf);
48 EXPECT_EQ(buf.space, space);
49 EXPECT_EQ(buf.flags & CX_BUFFER_AUTO_EXTEND, 0);
50 EXPECT_EQ(buf.flags & CX_BUFFER_FREE_CONTENTS, 0);
51 EXPECT_EQ(buf.pos, 0);
52 EXPECT_EQ(buf.size, 0);
53 EXPECT_EQ(buf.capacity, 16);
54 EXPECT_EQ(buf.allocator, &alloc);
55 cxBufferDestroy(&buf);
56 EXPECT_FALSE(alloc.verify());
57 cxFree(&alloc, space);
58 EXPECT_TRUE(alloc.verify());
59 }
61 TEST(BufferInit, WrapSpaceAutoExtend) {
62 CxTestingAllocator alloc;
63 CxBuffer buf;
64 void *space = cxMalloc(&alloc, 16);
65 cxBufferInit(&buf, space, 16, &alloc, CX_BUFFER_AUTO_EXTEND);
66 expect_default_flush_config(&buf);
67 EXPECT_EQ(buf.space, space);
68 EXPECT_EQ(buf.flags & CX_BUFFER_AUTO_EXTEND, CX_BUFFER_AUTO_EXTEND);
69 EXPECT_EQ(buf.flags & CX_BUFFER_FREE_CONTENTS, 0);
70 EXPECT_EQ(buf.pos, 0);
71 EXPECT_EQ(buf.size, 0);
72 EXPECT_EQ(buf.capacity, 16);
73 EXPECT_EQ(buf.allocator, &alloc);
74 cxBufferDestroy(&buf);
75 EXPECT_FALSE(alloc.verify());
76 cxFree(&alloc, space);
77 EXPECT_TRUE(alloc.verify());
78 }
80 TEST(BufferInit, WrapSpaceAutoFree) {
81 CxTestingAllocator alloc;
82 CxBuffer buf;
83 void *space = cxMalloc(&alloc, 16);
84 cxBufferInit(&buf, space, 16, &alloc, CX_BUFFER_FREE_CONTENTS);
85 expect_default_flush_config(&buf);
86 EXPECT_EQ(buf.space, space);
87 EXPECT_EQ(buf.flags & CX_BUFFER_AUTO_EXTEND, 0);
88 EXPECT_EQ(buf.flags & CX_BUFFER_FREE_CONTENTS, CX_BUFFER_FREE_CONTENTS);
89 EXPECT_EQ(buf.pos, 0);
90 EXPECT_EQ(buf.size, 0);
91 EXPECT_EQ(buf.capacity, 16);
92 EXPECT_EQ(buf.allocator, &alloc);
93 EXPECT_FALSE(alloc.verify());
94 cxBufferDestroy(&buf);
95 EXPECT_TRUE(alloc.verify());
96 }
98 TEST(BufferInit, FreshSpace) {
99 CxTestingAllocator alloc;
100 CxBuffer buf;
101 cxBufferInit(&buf, nullptr, 8, &alloc, CX_BUFFER_DEFAULT);
102 expect_default_flush_config(&buf);
103 EXPECT_NE(buf.space, nullptr);
104 EXPECT_EQ(buf.flags & CX_BUFFER_AUTO_EXTEND, 0);
105 EXPECT_EQ(buf.flags & CX_BUFFER_FREE_CONTENTS, CX_BUFFER_FREE_CONTENTS);
106 EXPECT_EQ(buf.pos, 0);
107 EXPECT_EQ(buf.size, 0);
108 EXPECT_EQ(buf.capacity, 8);
109 EXPECT_EQ(buf.allocator, &alloc);
110 EXPECT_FALSE(alloc.verify()); // space is still allocated
111 cxBufferDestroy(&buf);
112 EXPECT_TRUE(alloc.verify());
113 }
115 class BufferShiftFixture : public ::testing::Test {
116 protected:
117 void SetUp() override {
118 ASSERT_TRUE(alloc.verify());
119 cxBufferInit(&buf, nullptr, 16, &alloc, CX_BUFFER_DEFAULT);
120 memcpy(buf.space, "test____________", 16);
121 buf.capacity = 8; // purposely pretend that the buffer has less capacity s.t. we can test beyond the range
122 buf.pos = 4;
123 buf.size = 4;
124 }
126 void TearDown() override {
127 cxBufferDestroy(&buf);
128 EXPECT_TRUE(alloc.verify());
129 }
131 CxTestingAllocator alloc;
132 CxBuffer buf{};
133 };
135 class BufferShiftLeft : public BufferShiftFixture {
136 };
138 TEST_F(BufferShiftLeft, Zero) {
139 ASSERT_EQ(buf.pos, 4);
140 ASSERT_EQ(buf.size, 4);
141 int ret = cxBufferShiftLeft(&buf, 0);
142 EXPECT_EQ(ret, 0);
143 EXPECT_EQ(buf.pos, 4);
144 EXPECT_EQ(buf.size, 4);
145 EXPECT_TRUE(memcmp(buf.space, "test________", 8) == 0);
146 }
148 TEST_F(BufferShiftLeft, Standard) {
149 ASSERT_EQ(buf.pos, 4);
150 ASSERT_EQ(buf.size, 4);
151 int ret = cxBufferShiftLeft(&buf, 2);
152 EXPECT_EQ(ret, 0);
153 EXPECT_EQ(buf.pos, 2);
154 EXPECT_EQ(buf.size, 2);
155 EXPECT_TRUE(memcmp(buf.space, "stst________", 8) == 0);
156 }
158 TEST_F(BufferShiftLeft, Overshift) {
159 ASSERT_LT(buf.pos, 6);
160 ASSERT_LT(buf.size, 6);
161 int ret = cxBufferShiftLeft(&buf, 6);
162 EXPECT_EQ(ret, 0);
163 EXPECT_EQ(buf.pos, 0);
164 EXPECT_EQ(buf.size, 0);
165 EXPECT_TRUE(memcmp(buf.space, "test________", 8) == 0);
166 }
168 TEST_F(BufferShiftLeft, OvershiftPosOnly) {
169 buf.pos = 2;
170 ASSERT_EQ(buf.size, 4);
171 int ret = cxBufferShiftLeft(&buf, 3);
172 EXPECT_EQ(ret, 0);
173 EXPECT_EQ(buf.pos, 0);
174 EXPECT_EQ(buf.size, 1);
175 EXPECT_TRUE(memcmp(buf.space, "test________", 8) == 0);
176 }
178 TEST_F(BufferShiftLeft, OffsetInterface) {
179 buf.pos = 3;
180 ASSERT_EQ(buf.size, 4);
181 int ret = cxBufferShift(&buf, -2);
182 EXPECT_EQ(ret, 0);
183 EXPECT_EQ(buf.pos, 1);
184 EXPECT_EQ(buf.size, 2);
185 EXPECT_TRUE(memcmp(buf.space, "stst________", 8) == 0);
186 }
188 class BufferShiftRight : public BufferShiftFixture {
189 };
191 TEST_F(BufferShiftRight, Zero) {
192 ASSERT_EQ(buf.pos, 4);
193 ASSERT_EQ(buf.size, 4);
194 int ret = cxBufferShiftRight(&buf, 0);
195 EXPECT_EQ(ret, 0);
196 EXPECT_EQ(buf.pos, 4);
197 EXPECT_EQ(buf.size, 4);
198 EXPECT_TRUE(memcmp(buf.space, "test________", 8) == 0);
199 }
201 TEST_F(BufferShiftRight, Standard) {
202 ASSERT_EQ(buf.pos, 4);
203 ASSERT_EQ(buf.size, 4);
204 int ret = cxBufferShiftRight(&buf, 3);
205 EXPECT_EQ(ret, 0);
206 EXPECT_EQ(buf.pos, 7);
207 EXPECT_EQ(buf.size, 7);
208 EXPECT_TRUE(memcmp(buf.space, "testest_____", 8) == 0);
209 }
211 TEST_F(BufferShiftRight, OvershiftDiscard) {
212 ASSERT_EQ(buf.pos, 4);
213 ASSERT_EQ(buf.size, 4);
214 ASSERT_EQ(buf.capacity, 8);
215 int ret = cxBufferShiftRight(&buf, 6);
216 EXPECT_EQ(ret, 0);
217 EXPECT_EQ(buf.pos, 8);
218 EXPECT_EQ(buf.size, 8);
219 EXPECT_EQ(buf.capacity, 8);
220 EXPECT_TRUE(memcmp(buf.space, "test__te____", 8) == 0);
221 }
223 TEST_F(BufferShiftRight, OvershiftExtend) {
224 ASSERT_EQ(buf.pos, 4);
225 ASSERT_EQ(buf.size, 4);
226 ASSERT_EQ(buf.capacity, 8);
227 buf.flags |= CX_BUFFER_AUTO_EXTEND;
228 int ret = cxBufferShiftRight(&buf, 6);
229 EXPECT_EQ(ret, 0);
230 EXPECT_EQ(buf.pos, 10);
231 EXPECT_EQ(buf.size, 10);
232 EXPECT_GE(buf.capacity, 10);
233 EXPECT_TRUE(memcmp(buf.space, "test__test__", 8) == 0);
234 }
236 TEST_F(BufferShiftRight, OffsetInterface) {
237 buf.pos = 3;
238 ASSERT_EQ(buf.size, 4);
239 int ret = cxBufferShift(&buf, 2);
240 EXPECT_EQ(ret, 0);
241 EXPECT_EQ(buf.pos, 5);
242 EXPECT_EQ(buf.size, 6);
243 EXPECT_TRUE(memcmp(buf.space, "tetest______", 8) == 0);
244 }
246 TEST(BufferMinimumCapacity, Sufficient) {
247 CxTestingAllocator alloc;
248 auto space = cxMalloc(&alloc, 8);
249 CxBuffer buf;
250 cxBufferInit(&buf, space, 8, &alloc, CX_BUFFER_FREE_CONTENTS);
251 memcpy(space, "Testing", 8);
252 buf.size = 8;
253 cxBufferMinimumCapacity(&buf, 6);
254 EXPECT_EQ(buf.capacity, 8);
255 EXPECT_EQ(buf.size, 8);
256 EXPECT_TRUE(memcmp(buf.space, "Testing", 8) == 0);
257 cxBufferDestroy(&buf);
258 EXPECT_TRUE(alloc.verify());
259 }
261 TEST(BufferMinimumCapacity, Extend) {
262 CxTestingAllocator alloc;
263 auto space = cxMalloc(&alloc, 8);
264 CxBuffer buf;
265 cxBufferInit(&buf, space, 8, &alloc, CX_BUFFER_FREE_CONTENTS); // NO auto extend!
266 memcpy(space, "Testing", 8);
267 buf.size = 8;
268 cxBufferMinimumCapacity(&buf, 16);
269 EXPECT_EQ(buf.capacity, 16);
270 EXPECT_EQ(buf.size, 8);
271 EXPECT_TRUE(memcmp(buf.space, "Testing", 8) == 0);
272 cxBufferDestroy(&buf);
273 EXPECT_TRUE(alloc.verify());
274 }
276 TEST(BufferClear, Test) {
277 char space[16];
278 strcpy(space, "clear test");
279 CxBuffer buf;
280 cxBufferInit(&buf, space, 16, cxDefaultAllocator, CX_BUFFER_DEFAULT);
281 ASSERT_EQ(buf.size, 0);
282 // only clear the used part of the buffer
283 cxBufferClear(&buf);
284 EXPECT_EQ(memcmp(space, "clear test", 10), 0);
285 buf.size = 5;
286 buf.pos = 3;
287 cxBufferClear(&buf);
288 EXPECT_EQ(memcmp(space, "\0\0\0\0\0 test", 10), 0);
289 EXPECT_EQ(buf.size, 0);
290 EXPECT_EQ(buf.pos, 0);
291 cxBufferDestroy(&buf);
292 }
294 class BufferWrite : public ::testing::Test {
295 protected:
296 CxBuffer buf{};
298 void SetUp() override {
299 cxBufferInit(&buf, nullptr, 16, cxDefaultAllocator, CX_BUFFER_DEFAULT);
300 buf.capacity = 8; // artificially reduce capacity to check OOB writes
301 memset(buf.space, 0, 16);
302 memcpy(buf.space, "prep", 4);
303 buf.size = buf.pos = 4;
304 }
306 void TearDown() override {
307 cxBufferDestroy(&buf);
308 }
309 };
311 TEST_F(BufferWrite, SizeOneFit) {
312 const char *data = "test";
313 ASSERT_EQ(buf.capacity, 8);
314 ASSERT_EQ(buf.pos, 4);
315 ASSERT_EQ(buf.size, 4);
316 size_t written = cxBufferWrite(data, 1, 4, &buf);
317 EXPECT_EQ(written, 4);
318 EXPECT_EQ(buf.size, 8);
319 EXPECT_EQ(buf.pos, 8);
320 EXPECT_EQ(buf.capacity, 8);
321 EXPECT_EQ(memcmp(buf.space, "preptest", 8), 0);
322 }
324 TEST_F(BufferWrite, SizeOneDiscard) {
325 const char *data = "testing";
326 ASSERT_EQ(buf.capacity, 8);
327 ASSERT_EQ(buf.pos, 4);
328 ASSERT_EQ(buf.size, 4);
329 size_t written = cxBufferWrite(data, 1, 7, &buf);
330 EXPECT_EQ(written, 4);
331 EXPECT_EQ(buf.size, 8);
332 EXPECT_EQ(buf.pos, 8);
333 EXPECT_EQ(buf.capacity, 8);
334 EXPECT_EQ(memcmp(buf.space, "preptest\0", 9), 0);
335 }
337 TEST_F(BufferWrite, SizeOneExtend) {
338 buf.flags |= CX_BUFFER_AUTO_EXTEND;
339 const char *data = "testing";
340 ASSERT_EQ(buf.capacity, 8);
341 ASSERT_EQ(buf.pos, 4);
342 ASSERT_EQ(buf.size, 4);
343 size_t written = cxBufferWrite(data, 1, 7, &buf);
344 EXPECT_EQ(written, 7);
345 EXPECT_EQ(buf.size, 11);
346 EXPECT_EQ(buf.pos, 11);
347 EXPECT_GE(buf.capacity, 11);
348 EXPECT_EQ(memcmp(buf.space, "preptesting", 11), 0);
349 }
351 TEST_F(BufferWrite, MultibyteFit) {
352 const char *data = "test";
353 ASSERT_EQ(buf.capacity, 8);
354 ASSERT_EQ(buf.pos, 4);
355 ASSERT_EQ(buf.size, 4);
356 size_t written = cxBufferWrite(data, 2, 2, &buf);
357 EXPECT_EQ(written, 2);
358 EXPECT_EQ(buf.size, 8);
359 EXPECT_EQ(buf.pos, 8);
360 EXPECT_EQ(buf.capacity, 8);
361 EXPECT_EQ(memcmp(buf.space, "preptest", 8), 0);
362 }
364 TEST_F(BufferWrite, MultibyteDiscard) {
365 const char *data = "tester";
366 ASSERT_EQ(buf.capacity, 8);
367 ASSERT_EQ(buf.size, 4);
368 buf.pos = 3;
369 size_t written = cxBufferWrite(data, 2, 3, &buf);
370 // remember: whole elements are discarded if they do not fit
371 EXPECT_EQ(written, 2);
372 EXPECT_EQ(buf.size, 7);
373 EXPECT_EQ(buf.pos, 7);
374 EXPECT_EQ(buf.capacity, 8);
375 EXPECT_EQ(memcmp(buf.space, "pretest\0", 8), 0);
376 }
378 TEST_F(BufferWrite, MultibyteExtend) {
379 buf.flags |= CX_BUFFER_AUTO_EXTEND;
380 const char *data = "tester";
381 ASSERT_EQ(buf.capacity, 8);
382 ASSERT_EQ(buf.size, 4);
383 buf.pos = 3;
384 size_t written = cxBufferWrite(data, 2, 3, &buf);
385 // remember: whole elements are discarded if they do not fit
386 EXPECT_EQ(written, 3);
387 EXPECT_EQ(buf.size, 9);
388 EXPECT_EQ(buf.pos, 9);
389 EXPECT_GE(buf.capacity, 9);
390 EXPECT_EQ(memcmp(buf.space, "pretester\0", 10), 0);
391 }
393 TEST_F(BufferWrite, PutcWrapperFit) {
394 ASSERT_EQ(buf.capacity, 8);
395 ASSERT_EQ(buf.pos, 4);
396 ASSERT_EQ(buf.size, 4);
397 int c = cxBufferPut(&buf, 0x20 | 'a');
398 EXPECT_EQ(c, 'a');
399 EXPECT_EQ(buf.size, 5);
400 EXPECT_EQ(buf.pos, 5);
401 EXPECT_EQ(buf.capacity, 8);
402 EXPECT_EQ(memcmp(buf.space, "prepa\0", 6), 0);
403 }
405 TEST_F(BufferWrite, PutcWrapperDiscard) {
406 ASSERT_EQ(buf.capacity, 8);
407 ASSERT_EQ(buf.size, 4);
408 buf.pos = 8;
409 int c = cxBufferPut(&buf, 0x20 | 'a');
410 EXPECT_EQ(c, EOF);
411 EXPECT_EQ(buf.size, 4);
412 EXPECT_EQ(buf.pos, 8);
413 EXPECT_EQ(buf.capacity, 8);
414 EXPECT_EQ(memcmp(buf.space, "prep\0\0\0\0\0", 9), 0);
415 }
417 TEST_F(BufferWrite, PutcWrapperExtend) {
418 buf.flags |= CX_BUFFER_AUTO_EXTEND;
419 ASSERT_EQ(buf.capacity, 8);
420 ASSERT_EQ(buf.size, 4);
421 buf.pos = 8;
422 int c = cxBufferPut(&buf, 0x20 | 'a');
423 EXPECT_EQ(c, 'a');
424 EXPECT_EQ(buf.size, 9);
425 EXPECT_EQ(buf.pos, 9);
426 EXPECT_GE(buf.capacity, 9);
427 EXPECT_EQ(memcmp(buf.space, "prep\0\0\0\0a\0", 10), 0);
428 }
430 TEST_F(BufferWrite, PutStringWrapperFit) {
431 const char *data = "test";
432 ASSERT_EQ(buf.capacity, 8);
433 ASSERT_EQ(buf.pos, 4);
434 ASSERT_EQ(buf.size, 4);
435 size_t written = cxBufferPutString(&buf, data);
436 EXPECT_EQ(written, 4);
437 EXPECT_EQ(buf.size, 8);
438 EXPECT_EQ(buf.pos, 8);
439 EXPECT_EQ(buf.capacity, 8);
440 EXPECT_EQ(memcmp(buf.space, "preptest", 8), 0);
441 }
443 TEST_F(BufferWrite, PutStringWrapperDiscard) {
444 const char *data = "testing";
445 ASSERT_EQ(buf.capacity, 8);
446 ASSERT_EQ(buf.pos, 4);
447 ASSERT_EQ(buf.size, 4);
448 size_t written = cxBufferPutString(&buf, data);
449 EXPECT_EQ(written, 4);
450 EXPECT_EQ(buf.size, 8);
451 EXPECT_EQ(buf.pos, 8);
452 EXPECT_EQ(buf.capacity, 8);
453 EXPECT_EQ(memcmp(buf.space, "preptest\0", 9), 0);
454 }
456 TEST_F(BufferWrite, PutStringWrapperExtend) {
457 buf.flags |= CX_BUFFER_AUTO_EXTEND;
458 const char *data = "testing";
459 ASSERT_EQ(buf.capacity, 8);
460 ASSERT_EQ(buf.pos, 4);
461 ASSERT_EQ(buf.size, 4);
462 size_t written = cxBufferPutString(&buf, data);
463 EXPECT_EQ(written, 7);
464 EXPECT_EQ(buf.size, 11);
465 EXPECT_EQ(buf.pos, 11);
466 EXPECT_GE(buf.capacity, 11);
467 EXPECT_EQ(memcmp(buf.space, "preptesting", 11), 0);
468 }
470 TEST_F(BufferWrite, MultOverflow) {
471 const char *data = "testing";
472 ASSERT_EQ(buf.capacity, 8);
473 ASSERT_EQ(buf.pos, 4);
474 ASSERT_EQ(buf.size, 4);
475 size_t written = cxBufferWrite(data, 8, SIZE_MAX / 4, &buf);
476 EXPECT_EQ(written, 0);
477 EXPECT_EQ(buf.capacity, 8);
478 EXPECT_EQ(buf.pos, 4);
479 EXPECT_EQ(buf.size, 4);
480 EXPECT_EQ(memcmp(buf.space, "prep\0", 5), 0);
481 }
483 TEST_F(BufferWrite, MaxCapaOverflow) {
484 buf.flags |= CX_BUFFER_AUTO_EXTEND;
485 const char *data = "testing";
486 ASSERT_EQ(buf.capacity, 8);
487 ASSERT_EQ(buf.pos, 4);
488 ASSERT_EQ(buf.size, 4);
489 size_t written = cxBufferWrite(data, 1, SIZE_MAX - 2, &buf);
490 EXPECT_EQ(written, 0);
491 EXPECT_EQ(buf.capacity, 8);
492 EXPECT_EQ(buf.pos, 4);
493 EXPECT_EQ(buf.size, 4);
494 EXPECT_EQ(memcmp(buf.space, "prep\0", 5), 0);
495 }
497 TEST_F(BufferWrite, OnlyOverwrite) {
498 buf.flags |= CX_BUFFER_AUTO_EXTEND;
499 ASSERT_EQ(buf.capacity, 8);
500 memcpy(buf.space, "preptest", 8);
501 buf.pos = 3;
502 buf.size = 8;
503 size_t written = cxBufferWrite("XXX", 2, 2, &buf);
504 EXPECT_EQ(written, 2);
505 EXPECT_EQ(buf.capacity, 8);
506 EXPECT_EQ(buf.size, 8);
507 EXPECT_EQ(buf.pos, 7);
508 EXPECT_EQ(memcmp(buf.space, "preXXX\0t", 8), 0);
509 }
