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test: Migrate unit tests to gtest, integrate with CI (#2144)

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This commit is contained in:
Zach Nelson
2026-05-25 15:51:53 -07:00
committed by GitHub
parent 4ee406897b
commit 6dbfc29c7e
17 changed files with 696 additions and 1368 deletions
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test/differential_rounding/DifferentialRoundingTest.cpp
+99 -207
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@@ -1,34 +1,11 @@
#include <cassert>
#include <gtest/gtest.h>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include "lib/EpdFont/EpdFont.h"
#include "lib/EpdFont/EpdFontData.h"
static int testsPassed = 0;
static int testsFailed = 0;
#define ASSERT_EQ(a, b) \
do { \
if ((a) != (b)) { \
fprintf(stderr, " FAIL: %s:%d: %s == %d, expected %d\n", __FILE__, __LINE__, #a, (a), (b)); \
testsFailed++; \
return; \
} \
} while (0)
#define ASSERT_TRUE(cond) \
do { \
if (!(cond)) { \
fprintf(stderr, " FAIL: %s:%d: %s\n", __FILE__, __LINE__, #cond); \
testsFailed++; \
return; \
} \
} while (0)
#define PASS() testsPassed++
// ============================================================================
// Synthetic test font
//
@@ -43,8 +20,10 @@ static int testsFailed = 0;
// o->a: -2 (-0.125px) o->o: -3 (-0.1875px)
// ============================================================================
namespace {
// clang-format off
static const EpdGlyph kGlyphs[] = {
const EpdGlyph kGlyphs[] = {
// idx width height advanceX left top dataLength dataOffset
/* 0 'T' */ { 8, 12, 137, 0, 12, 0, 0 },
/* 1 'a' */ { 7, 8, 130, 0, 8, 0, 0 },
@@ -52,28 +31,28 @@ static const EpdGlyph kGlyphs[] = {
/* 3 'x' */ { 7, 8, 136, 0, 8, 0, 0 },
};
static const EpdUnicodeInterval kIntervals[] = {
const EpdUnicodeInterval kIntervals[] = {
{ 0x54, 0x54, 0 }, // 'T' -> glyph[0]
{ 0x61, 0x61, 1 }, // 'a' -> glyph[1]
{ 0x6F, 0x6F, 2 }, // 'o' -> glyph[2]
{ 0x78, 0x78, 3 }, // 'x' -> glyph[3]
};
static const EpdKernClassEntry kKernLeft[] = {
const EpdKernClassEntry kKernLeft[] = {
{ 0x54, 1 }, // 'T' -> left class 1
{ 0x6F, 2 }, // 'o' -> left class 2
};
static const EpdKernClassEntry kKernRight[] = {
const EpdKernClassEntry kKernRight[] = {
{ 0x61, 1 }, // 'a' -> right class 1
{ 0x6F, 2 }, // 'o' -> right class 2
};
// Flat matrix: leftClassCount(2) x rightClassCount(2), 4.4 fixed-point
// [L1,R1]=kern(T,a) [L1,R2]=kern(T,o) [L2,R1]=kern(o,a) [L2,R2]=kern(o,o)
static const int8_t kKernMatrix[] = { -5, -7, -2, -3 };
const int8_t kKernMatrix[] = { -5, -7, -2, -3 };
static const EpdFontData kTestFontData = {
const EpdFontData kTestFontData = {
.bitmap = nullptr,
.glyph = kGlyphs,
.intervals = kIntervals,
@@ -94,62 +73,63 @@ static const EpdFontData kTestFontData = {
.kernRightClassCount = 2,
.ligaturePairs = nullptr,
.ligaturePairCount = 0,
.glyphMissHandler = nullptr,
.glyphMissCtx = nullptr,
};
// clang-format on
static EpdFont testFont(&kTestFontData);
EpdFont& testFont() {
static EpdFont font(&kTestFontData);
return font;
}
// Helper: return width from getTextDimensions
static int textWidth(const char* str) {
int textWidth(const char* str) {
int w = 0, h = 0;
testFont.getTextDimensions(str, &w, &h);
testFont().getTextDimensions(str, &w, &h);
return w;
}
static int textHeight(const char* str) {
int textHeight(const char* str) {
int w = 0, h = 0;
testFont.getTextDimensions(str, &w, &h);
testFont().getTextDimensions(str, &w, &h);
return h;
}
// Simulate the old absolute-snap gap for comparison
int absoluteGap(int32_t startFP, int32_t advanceFP, int32_t kernFP) {
int32_t nextFP = startFP + advanceFP + kernFP;
return fp4::toPixel(nextFP) - fp4::toPixel(startFP);
}
} // namespace
// ============================================================================
// Part 1: Pure fp4 math tests
// ============================================================================
// Simulate the old absolute-snap gap for comparison
static int absoluteGap(int32_t startFP, int32_t advanceFP, int32_t kernFP) {
int32_t nextFP = startFP + advanceFP + kernFP;
return fp4::toPixel(nextFP) - fp4::toPixel(startFP);
}
void testFp4Basics() {
printf("testFp4Basics...\n");
TEST(Fp4Math, RoundTripIntegerPixels) {
for (int px = 0; px < 500; px++) {
ASSERT_EQ(fp4::toPixel(fp4::fromPixel(px)), px);
EXPECT_EQ(fp4::toPixel(fp4::fromPixel(px)), px) << "px=" << px;
}
ASSERT_EQ(fp4::toPixel(0), 0);
ASSERT_EQ(fp4::toPixel(7), 0); // 0.4375 -> 0
ASSERT_EQ(fp4::toPixel(8), 1); // 0.5 -> 1 (round half up)
ASSERT_EQ(fp4::toPixel(15), 1); // 0.9375 -> 1
ASSERT_EQ(fp4::toPixel(16), 1); // 1.0 -> 1
ASSERT_EQ(fp4::toPixel(24), 2); // 1.5 -> 2
ASSERT_EQ(fp4::toPixel(-8), 0); // -0.5 -> 0
ASSERT_EQ(fp4::toPixel(-9), -1); // -0.5625 -> -1
ASSERT_EQ(fp4::toPixel(-16), -1);
ASSERT_EQ(fp4::toPixel(137 + (-9)), 8); // 128 = 8.0 exact
ASSERT_EQ(fp4::toPixel(137 + (-5)), 8); // 132 = 8.25
ASSERT_EQ(fp4::toPixel(137 + (-1)), 9); // 136 = 8.5 (half rounds up)
printf(" All fp4 basics passed\n");
PASS();
}
void testOldApproachInconsistency() {
printf("testOldApproachInconsistency...\n");
TEST(Fp4Math, RoundingBoundaries) {
EXPECT_EQ(fp4::toPixel(0), 0);
EXPECT_EQ(fp4::toPixel(7), 0); // 0.4375 -> 0
EXPECT_EQ(fp4::toPixel(8), 1); // 0.5 -> 1 (round half up)
EXPECT_EQ(fp4::toPixel(15), 1); // 0.9375 -> 1
EXPECT_EQ(fp4::toPixel(16), 1); // 1.0 -> 1
EXPECT_EQ(fp4::toPixel(24), 2); // 1.5 -> 2
EXPECT_EQ(fp4::toPixel(-8), 0); // -0.5 -> 0
EXPECT_EQ(fp4::toPixel(-9), -1); // -0.5625 -> -1
EXPECT_EQ(fp4::toPixel(-16), -1);
EXPECT_EQ(fp4::toPixel(137 + (-9)), 8); // 128 = 8.0 exact
EXPECT_EQ(fp4::toPixel(137 + (-5)), 8); // 132 = 8.25
EXPECT_EQ(fp4::toPixel(137 + (-1)), 9); // 136 = 8.5 (half rounds up)
}
TEST(Fp4Math, OldApproachInconsistency) {
// 'oo' pair: advance=145 (9.0625px), kern=-3 (-0.1875px), combined=142 (8.875px)
const int32_t advance = 145;
const int32_t kern = -3;
@@ -164,76 +144,51 @@ void testOldApproachInconsistency() {
}
}
ASSERT_TRUE(maxGap - minGap >= 1);
printf(" Old absolute gap range: [%d, %d] -- varies by %d px\n", minGap, maxGap, maxGap - minGap);
int diffStep = fp4::toPixel(advance + kern);
printf(" Differential step: always %d px\n", diffStep);
PASS();
// Absolute snap produces inconsistent gaps depending on subpixel phase.
EXPECT_GE(maxGap - minGap, 1);
}
void testExhaustiveKernRange() {
printf("testExhaustiveKernRange...\n");
TEST(Fp4Math, ExhaustiveKernRange) {
const int32_t baseAdvance = 128;
int checked = 0;
for (int advFrac = 0; advFrac < 16; advFrac++) {
int32_t advance = baseAdvance + advFrac;
for (int kern = -128; kern <= 127; kern++) {
int step = fp4::toPixel(advance + static_cast<int32_t>(kern));
float idealPx = fp4::toFloat(advance + kern);
if (std::abs(step - idealPx) >= 1.0f) {
fprintf(stderr, " FAIL: advance=%d, kern=%d, step=%d, ideal=%.4f\n", advance, kern, step, idealPx);
testsFailed++;
return;
}
checked++;
EXPECT_LT(std::abs(step - idealPx), 1.0f) << "advance=" << advance << " kern=" << kern;
}
}
printf(" Checked %d (advance, kern) combinations -- all within 1px of ideal\n", checked);
PASS();
}
// ============================================================================
// Part 2: Integration tests using real EpdFont::getTextDimensions
// ============================================================================
void testKernLookup() {
printf("testKernLookup...\n");
ASSERT_EQ(testFont.getKerning('T', 'a'), -5);
ASSERT_EQ(testFont.getKerning('T', 'o'), -7);
ASSERT_EQ(testFont.getKerning('o', 'a'), -2);
ASSERT_EQ(testFont.getKerning('o', 'o'), -3);
ASSERT_EQ(testFont.getKerning('a', 'o'), 0); // 'a' has no left class
ASSERT_EQ(testFont.getKerning('x', 'o'), 0); // 'x' has no left class
ASSERT_EQ(testFont.getKerning('T', 'x'), 0); // 'x' has no right class
ASSERT_EQ(testFont.getKerning('T', 'T'), 0); // 'T' has no right class
printf(" All kern lookups correct\n");
PASS();
TEST(EpdFont, KernLookup) {
EXPECT_EQ(testFont().getKerning('T', 'a'), -5);
EXPECT_EQ(testFont().getKerning('T', 'o'), -7);
EXPECT_EQ(testFont().getKerning('o', 'a'), -2);
EXPECT_EQ(testFont().getKerning('o', 'o'), -3);
EXPECT_EQ(testFont().getKerning('a', 'o'), 0); // 'a' has no left class
EXPECT_EQ(testFont().getKerning('x', 'o'), 0); // 'x' has no left class
EXPECT_EQ(testFont().getKerning('T', 'x'), 0); // 'x' has no right class
EXPECT_EQ(testFont().getKerning('T', 'T'), 0); // 'T' has no right class
}
void testGlyphLookup() {
printf("testGlyphLookup...\n");
ASSERT_TRUE(testFont.getGlyph('T') != nullptr);
ASSERT_TRUE(testFont.getGlyph('a') != nullptr);
ASSERT_TRUE(testFont.getGlyph('o') != nullptr);
ASSERT_TRUE(testFont.getGlyph('x') != nullptr);
ASSERT_EQ(testFont.getGlyph('T')->advanceX, 137);
ASSERT_EQ(testFont.getGlyph('a')->advanceX, 130);
ASSERT_EQ(testFont.getGlyph('o')->advanceX, 145);
ASSERT_EQ(testFont.getGlyph('x')->advanceX, 136);
TEST(EpdFont, GlyphLookup) {
ASSERT_NE(testFont().getGlyph('T'), nullptr);
ASSERT_NE(testFont().getGlyph('a'), nullptr);
ASSERT_NE(testFont().getGlyph('o'), nullptr);
ASSERT_NE(testFont().getGlyph('x'), nullptr);
EXPECT_EQ(testFont().getGlyph('T')->advanceX, 137);
EXPECT_EQ(testFont().getGlyph('a')->advanceX, 130);
EXPECT_EQ(testFont().getGlyph('o')->advanceX, 145);
EXPECT_EQ(testFont().getGlyph('x')->advanceX, 136);
// No U+FFFD in font, so unknown codepoints return nullptr
ASSERT_TRUE(testFont.getGlyph('Z') == nullptr);
ASSERT_TRUE(testFont.getGlyph('b') == nullptr);
printf(" All glyph lookups correct\n");
PASS();
EXPECT_EQ(testFont().getGlyph('Z'), nullptr);
EXPECT_EQ(testFont().getGlyph('b'), nullptr);
}
// Known-value regression tests. Expected widths are computed by hand using
@@ -245,45 +200,32 @@ void testGlyphLookup() {
//
// Differential step from glyph A to glyph B:
// step = fp4::toPixel(advanceA + kern(A,B))
void testKnownWidths() {
printf("testKnownWidths...\n");
// "o": single glyph at x=0, width=8
// w = 0 + 8 = 8
ASSERT_EQ(textWidth("o"), 8);
TEST(EpdFont, KnownWidths) {
// "o": single glyph at x=0, width=8 -> w = 0 + 8 = 8
EXPECT_EQ(textWidth("o"), 8);
// "oo": step = toPixel(145 + (-3)) = toPixel(142) = 9
// o1 at 0, o2 at 9. w = 9 + 8 = 17
ASSERT_EQ(textWidth("oo"), 17);
EXPECT_EQ(textWidth("oo"), 17);
// "ooo": two steps of 9
// o1 at 0, o2 at 9, o3 at 18. w = 18 + 8 = 26
ASSERT_EQ(textWidth("ooo"), 26);
// "ooo": two steps of 9 -> o3 at 18, w = 18 + 8 = 26
EXPECT_EQ(textWidth("ooo"), 26);
// "To": step = toPixel(137 + (-7)) = toPixel(130) = 8
// T at 0, o at 8. w = 8 + 8 = 16
ASSERT_EQ(textWidth("To"), 16);
// "To": step = toPixel(137 + (-7)) = 8 -> o at 8, w = 8 + 8 = 16
EXPECT_EQ(textWidth("To"), 16);
// "Ta": step = toPixel(137 + (-5)) = toPixel(132) = 8
// T at 0, a at 8. w = 8 + 7 = 15
ASSERT_EQ(textWidth("Ta"), 15);
// "Ta": step = toPixel(137 + (-5)) = 8 -> a at 8, w = 8 + 7 = 15
EXPECT_EQ(textWidth("Ta"), 15);
// "oa": step = toPixel(145 + (-2)) = toPixel(143) = 9
// o at 0, a at 9. w = 9 + 7 = 16
ASSERT_EQ(textWidth("oa"), 16);
// "oa": step = toPixel(145 + (-2)) = 9 -> a at 9, w = 9 + 7 = 16
EXPECT_EQ(textWidth("oa"), 16);
// "Too": T at 0.
// step T->o = toPixel(137 + (-7)) = 8. o1 at 8.
// step o->o = toPixel(145 + (-3)) = 9. o2 at 17.
// w = 17 + 8 = 25
ASSERT_EQ(textWidth("Too"), 25);
// "Too": T at 0, o1 at 8 (T->o step), o2 at 17 (o->o step). w = 17 + 8 = 25
EXPECT_EQ(textWidth("Too"), 25);
// "xo": step = toPixel(136 + 0) = toPixel(136) = 9 (no kern: x has no left class)
// "xo": step = toPixel(136 + 0) = 9 (no kern: x has no left class)
// x at 0, o at 9. w = 9 + 8 = 17
ASSERT_EQ(textWidth("xo"), 17);
printf(" All known widths correct\n");
PASS();
EXPECT_EQ(textWidth("xo"), 17);
}
// "oo" pair consistency: the pixel gap between two o's must be the same
@@ -291,9 +233,7 @@ void testKnownWidths() {
// differential rounding. With absolute snapping, "xoo" would produce a
// different oo gap than "oo" because 'x' advance (136 FP) puts the first
// 'o' at fractional phase 8, crossing the rounding boundary differently.
void testPairConsistencyViaFont() {
printf("testPairConsistencyViaFont...\n");
TEST(EpdFont, PairConsistencyViaFont) {
// The oo gap = width(prefix + "oo") - width(prefix + "o")
// This isolates the pixel distance contributed by the second 'o'.
const int oo_gap_bare = textWidth("oo") - textWidth("o");
@@ -301,81 +241,33 @@ void testPairConsistencyViaFont() {
const int oo_gap_after_T = textWidth("Too") - textWidth("To");
const int oo_gap_after_o = textWidth("ooo") - textWidth("oo");
printf(" oo gap (bare): %d\n", oo_gap_bare);
printf(" oo gap (after x): %d\n", oo_gap_after_x);
printf(" oo gap (after T): %d\n", oo_gap_after_T);
printf(" oo gap (after o): %d\n", oo_gap_after_o);
// All must be identical
ASSERT_EQ(oo_gap_after_x, oo_gap_bare);
ASSERT_EQ(oo_gap_after_T, oo_gap_bare);
ASSERT_EQ(oo_gap_after_o, oo_gap_bare);
printf(" All oo gaps identical (%d px) regardless of prefix\n", oo_gap_bare);
PASS();
EXPECT_EQ(oo_gap_after_x, oo_gap_bare);
EXPECT_EQ(oo_gap_after_T, oo_gap_bare);
EXPECT_EQ(oo_gap_after_o, oo_gap_bare);
}
// Null-glyph handling: when a codepoint has no glyph (and no replacement
// glyph), the pending advance from the previous glyph must still be flushed.
// Without the flush fix, the glyph after the null would overlap the one before.
void testNullGlyphAdvancePreserved() {
printf("testNullGlyphAdvancePreserved...\n");
TEST(EpdFont, NullGlyphAdvancePreserved) {
// 'Z' (0x5A) is not in our font and there's no U+FFFD, so getGlyph returns null.
// "oZo" should lay out as: o1 at 0, Z skipped (advance flushed), o2 at 9.
// toPixel(145) = 9 (o's advance, no kern since Z resets prevCp).
// w = 9 + 8 = 17
int w = textWidth("oZo");
printf(" width(\"oZo\") = %d\n", w);
// Without the flush fix, o2 would land at 0 (overlapping o1), giving w = 8.
ASSERT_TRUE(w > 8);
ASSERT_EQ(w, 17);
EXPECT_EQ(textWidth("oZo"), 17);
// Multi-null: "oZZo" -- two consecutive nulls, advance still preserved.
w = textWidth("oZZo");
printf(" width(\"oZZo\") = %d\n", w);
ASSERT_EQ(w, 17);
EXPECT_EQ(textWidth("oZZo"), 17);
// Null at start: "Zo" -- no pending advance to flush, o renders at 0.
w = textWidth("Zo");
printf(" width(\"Zo\") = %d\n", w);
ASSERT_EQ(w, 8);
printf(" Null-glyph advance correctly preserved\n");
PASS();
EXPECT_EQ(textWidth("Zo"), 8);
}
void testHeightCalculation() {
printf("testHeightCalculation...\n");
TEST(EpdFont, HeightCalculation) {
// 'T' is tallest: top=12, height=12 -> extent [0, 12)
// 'o' and 'a': top=8, height=8 -> extent [0, 8)
ASSERT_EQ(textHeight("o"), 8);
ASSERT_EQ(textHeight("T"), 12);
ASSERT_EQ(textHeight("To"), 12);
ASSERT_EQ(textHeight("oo"), 8);
printf(" All heights correct\n");
PASS();
}
int main() {
printf("=== Differential Rounding Tests ===\n\n");
// Part 1: Pure fp4 math
testFp4Basics();
testOldApproachInconsistency();
testExhaustiveKernRange();
// Part 2: Integration tests against real EpdFont
testKernLookup();
testGlyphLookup();
testKnownWidths();
testPairConsistencyViaFont();
testNullGlyphAdvancePreserved();
testHeightCalculation();
printf("\n=== Results: %d passed, %d failed ===\n", testsPassed, testsFailed);
return testsFailed > 0 ? 1 : 0;
EXPECT_EQ(textHeight("o"), 8);
EXPECT_EQ(textHeight("T"), 12);
EXPECT_EQ(textHeight("To"), 12);
EXPECT_EQ(textHeight("oo"), 8);
}