Function TEST_F

third-party/yoga/test/TabsHeaderLayout_test.cpp:137–171

Core test: labels inside percentage-width flex children should have non-zero width after layout. If they don't, the tab labels are invisible.

// Core test: labels inside percentage-width flex children should have
// non-zero width after layout. If they don't, the tab labels are invisible.
TEST_F(TabBarLayoutTest, tabLabelsGetNonZeroWidth) {
    auto l = buildTabBar(2);
    g_measureRecords.clear();

    // Parent container size: iPhone 14 Pro (393×44 for tab bar area)
    YGNodeCalculateLayout(l.root, 393, 44, YGDirectionLTR);

    float label0Width = YGNodeLayoutGetWidth(l.label0);
    float label1Width = YGNodeLayoutGetWidth(l.label1);

    // Dump measure constraints for debugging
    for (size_t i = 0; i < g_measureRecords.size(); i++) {
        const auto& r = g_measureRecords[i];
        const char* wMode = r.widthMode == YGMeasureModeExactly ? "Exactly" :
                           r.widthMode == YGMeasureModeAtMost ? "AtMost" : "Undefined";
        const char* hMode = r.heightMode == YGMeasureModeExactly ? "Exactly" :
                           r.heightMode == YGMeasureModeAtMost ? "AtMost" : "Undefined";
        fprintf(stderr, "Measure[%zu]: w=%.1f(%s) h=%.1f(%s)\n",
                i, r.width, wMode, r.height, hMode);
    }

    fprintf(stderr, "label0: %.1f x %.1f\n", label0Width, YGNodeLayoutGetHeight(l.label0));
    fprintf(stderr, "label1: %.1f x %.1f\n", label1Width, YGNodeLayoutGetHeight(l.label1));
    fprintf(stderr, "item0: %.1f x %.1f\n",
            YGNodeLayoutGetWidth(l.item0), YGNodeLayoutGetHeight(l.item0));
    fprintf(stderr, "itemContainer: %.1f x %.1f\n",
            YGNodeLayoutGetWidth(l.itemContainer), YGNodeLayoutGetHeight(l.itemContainer));
    fprintf(stderr, "scrollView: %.1f x %.1f\n",
            YGNodeLayoutGetWidth(l.scrollView), YGNodeLayoutGetHeight(l.scrollView));

    EXPECT_GT(label0Width, 0)
        << "Label 0 has zero width — tab name invisible.";
    EXPECT_GT(label1Width, 0)
        << "Label 1 has zero width — tab name invisible.";
}

// Verify measure function is NOT called with zero-width constraints
TEST_F(TabBarLayoutTest, measureFunctionNeverGetsZeroWidthConstraint) {