Add m-esr52 at 52.6.0

1 files changed, 1398 insertions, 0 deletions

diff --git a/layout/style/test/flexbox_layout_testcases.js b/layout/style/test/flexbox_layout_testcases.js
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+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ts=2 sw=2 sts=2 et: */
+
+/*
+ * This Source Code is subject to the terms of the Mozilla Public License
+ * version 2.0 (the "License"). You can obtain a copy of the License at
+ * http://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * For the purposes of this test, flex items are specified as a hash with a
+ * hash-entry for each CSS property that is to be set.  In these per-property
+ * entries, the key is the property-name, and the value can be either of the
+ * following:
+ *  (a) the property's specified value (which indicates that we don't need to
+ *      bother checking the computed value of this particular property)
+ *  ...OR...
+ *  (b) an array with 2-3 entries...
+ *        [specifiedValue, expectedComputedValue (, epsilon) ]
+ *      ...which indicates that the property's computed value should be
+ *      checked.  The array's first entry (for the specified value) may be
+ *      null; this means that no value should be explicitly specified for this
+ *      property. The second entry is the property's expected computed
+ *      value. The third (optional) entry is an epsilon value, which allows for
+ *      fuzzy equality when testing the computed value.
+ *
+ * To allow these testcases to be re-used in both horizontal and vertical
+ * flex containers, we specify "width"/"min-width"/etc. using the aliases
+ * "_main-size", "_min-main-size", etc.  The test code can map these
+ * placeholder names to their corresponding property-names using the maps
+ * defined below -- gRowPropertyMapping, gColumnPropertyMapping, etc.
+ *
+ * If the testcase needs to customize its flex container at all (e.g. by
+ * specifying a custom container-size), it can do so by including a hash
+ * called "container_properties", with propertyName:propertyValue mappings.
+ * (This hash can use aliased property-names like "_main-size" as well.)
+ */
+
+// The standard main-size we'll use for our flex container when setting up
+// the testcases defined below:
+var gDefaultFlexContainerSize = "200px";
+
+// Left-to-right versions of placeholder property-names used in
+// testcases below:
+var gRowPropertyMapping =
+{
+  "_main-size":               "width",
+  "_min-main-size":           "min-width",
+  "_max-main-size":           "max-width",
+  "_border-main-start-width": "border-left-width",
+  "_border-main-end-width":   "border-right-width",
+  "_padding-main-start":      "padding-left",
+  "_padding-main-end":        "padding-right",
+  "_margin-main-start":       "margin-left",
+  "_margin-main-end":         "margin-right"
+};
+
+// Right-to-left versions of placeholder property-names used in
+// testcases below:
+var gRowReversePropertyMapping =
+{
+  "_main-size":               "width",
+  "_min-main-size":           "min-width",
+  "_max-main-size":           "max-width",
+  "_border-main-start-width": "border-right-width",
+  "_border-main-end-width":   "border-left-width",
+  "_padding-main-start":      "padding-right",
+  "_padding-main-end":        "padding-left",
+  "_margin-main-start":       "margin-right",
+  "_margin-main-end":         "margin-left"
+};
+
+// Top-to-bottom versions of placeholder property-names used in
+// testcases below:
+var gColumnPropertyMapping =
+{
+  "_main-size":               "height",
+  "_min-main-size":           "min-height",
+  "_max-main-size":           "max-height",
+  "_border-main-start-width": "border-top-width",
+  "_border-main-end-width":   "border-bottom-width",
+  "_padding-main-start":      "padding-top",
+  "_padding-main-end":        "padding-bottom",
+  "_margin-main-start":       "margin-top",
+  "_margin-main-end":         "margin-bottom"
+};
+
+// Bottom-to-top versions of placeholder property-names used in
+// testcases below:
+var gColumnReversePropertyMapping =
+{
+  "_main-size":               "height",
+  "_min-main-size":           "min-height",
+  "_max-main-size":           "max-height",
+  "_border-main-start-width": "border-bottom-width",
+  "_border-main-end-width":   "border-top-width",
+  "_padding-main-start":      "padding-bottom",
+  "_padding-main-end":        "padding-top",
+  "_margin-main-start":       "margin-bottom",
+  "_margin-main-end":         "margin-top"
+};
+
+// The list of actual testcase definitions:
+var gFlexboxTestcases =
+[
+ // No flex properties specified --> should just use 'width' for sizing
+ {
+   items:
+     [
+       { "_main-size": [ "40px", "40px" ] },
+       { "_main-size": [ "65px", "65px" ] },
+     ]
+ },
+ // flex-basis is specified:
+ {
+   items:
+     [
+       { "flex-basis": "50px",
+         "_main-size": [ null,  "50px" ]
+       },
+       {
+         "flex-basis": "20px",
+         "_main-size": [ null, "20px" ]
+       },
+     ]
+ },
+ // flex-basis is *large* -- sum of flex-basis values is > flex container size:
+ // (w/ 0 flex-shrink so we don't shrink):
+ {
+   items:
+     [
+       {
+         "flex": "0 0 150px",
+         "_main-size": [ null, "150px" ]
+       },
+       {
+         "flex": "0 0 90px",
+         "_main-size": [ null, "90px" ]
+       },
+     ]
+ },
+ // flex-basis is *large* -- each flex-basis value is > flex container size:
+ // (w/ 0 flex-shrink so we don't shrink):
+ {
+   items:
+     [
+       {
+         "flex": "0 0 250px",
+         "_main-size": [ null, "250px" ]
+       },
+       {
+         "flex": "0 0 400px",
+         "_main-size": [ null, "400px" ]
+       },
+     ]
+ },
+ // flex-basis has percentage value:
+ {
+   items:
+     [
+       {
+         "flex-basis": "30%",
+         "_main-size": [ null, "60px" ]
+       },
+       {
+         "flex-basis": "45%",
+         "_main-size": [ null, "90px" ]
+       },
+     ]
+ },
+ // flex-basis has calc(percentage) value:
+ {
+   items:
+     [
+       {
+         "flex-basis": "calc(20%)",
+         "_main-size": [ null, "40px" ]
+       },
+       {
+         "flex-basis": "calc(80%)",
+         "_main-size": [ null, "160px" ]
+       },
+     ]
+ },
+ // flex-basis has calc(percentage +/- length) value:
+ {
+   items:
+     [
+       {
+         "flex-basis": "calc(10px + 20%)",
+         "_main-size": [ null, "50px" ]
+       },
+       {
+         "flex-basis": "calc(60% - 1px)",
+         "_main-size": [ null, "119px" ]
+       },
+     ]
+ },
+ // flex-grow is specified:
+ {
+   items:
+     [
+       {
+         "flex": "1",
+         "_main-size": [ null,  "60px" ]
+       },
+       {
+         "flex": "2",
+         "_main-size": [ null, "120px" ]
+       },
+       {
+         "flex": "0 20px",
+         "_main-size": [ null, "20px" ]
+       }
+     ]
+ },
+ // Same ratio as prev. testcase; making sure we handle float inaccuracy
+ {
+   items:
+     [
+       {
+         "flex": "100000",
+         "_main-size": [ null,  "60px" ]
+       },
+       {
+         "flex": "200000",
+         "_main-size": [ null, "120px" ]
+       },
+       {
+         "flex": "0.000001 20px",
+         "_main-size": [ null,  "20px" ]
+       }
+     ]
+ },
+ // Same ratio as prev. testcase, but with items cycled and w/
+ // "flex: none" & explicit size instead of "flex: 0 20px"
+ {
+   items:
+     [
+       {
+         "flex": "none",
+         "_main-size": [ "20px", "20px" ]
+       },
+       {
+         "flex": "1",
+         "_main-size": [ null,   "60px" ]
+       },
+       {
+         "flex": "2",
+         "_main-size": [ null,  "120px" ]
+       }
+     ]
+ },
+
+ // ...and now with flex-grow:[huge] to be sure we handle infinite float values
+ // gracefully.
+ {
+   items:
+     [
+       {
+         "flex": "9999999999999999999999999999999999999999999999999999999",
+         "_main-size": [ null,  "200px" ]
+       },
+     ]
+ },
+ {
+   items:
+     [
+       {
+         "flex": "9999999999999999999999999999999999999999999999999999999",
+         "_main-size": [ null,  "50px" ]
+       },
+       {
+         "flex": "9999999999999999999999999999999999999999999999999999999",
+         "_main-size": [ null,  "50px" ]
+       },
+       {
+         "flex": "9999999999999999999999999999999999999999999999999999999",
+         "_main-size": [ null,  "50px" ]
+       },
+       {
+         "flex": "9999999999999999999999999999999999999999999999999999999",
+         "_main-size": [ null,  "50px" ]
+       },
+     ]
+ },
+ {
+   items:
+     [
+       {
+         "flex": "99999999999999999999999999999999999",
+         "_main-size": [ null,  "50px" ]
+       },
+       {
+         "flex": "99999999999999999999999999999999999",
+         "_main-size": [ null,  "50px" ]
+       },
+       {
+         "flex": "99999999999999999999999999999999999",
+         "_main-size": [ null,  "50px" ]
+       },
+       {
+         "flex": "99999999999999999999999999999999999",
+         "_main-size": [ null,  "50px" ]
+       },
+     ]
+ },
+
+ // And now, some testcases to check that we handle float accumulation error
+ // gracefully.
+
+ // First, a testcase with just a custom-sized huge container, to be sure we'll
+ // be able to handle content on that scale, in the subsequent more-complex
+ // testcases:
+ {
+   container_properties:
+   {
+     "_main-size": "9000000px"
+   },
+   items:
+     [
+       {
+         "flex": "1",
+         "_main-size": [ null,  "9000000px" ]
+       },
+     ]
+ },
+ // ...and now with two flex items dividing up that container's huge size:
+ {
+   container_properties:
+   {
+     "_main-size": "9000000px"
+   },
+   items:
+     [
+       {
+         "flex": "2",
+         "_main-size": [ null,  "6000000px" ]
+       },
+       {
+         "flex": "1",
+         "_main-size": [ null,  "3000000px" ]
+       },
+     ]
+ },
+
+ // OK, now to actually test accumulation error. Below, we have six flex items
+ // splitting up the container's size, with huge differences between flex
+ // weights.  For simplicity, I've set up the weights so that they sum exactly
+ // to the container's size in px. So 1 unit of flex *should* get you 1px.
+ //
+ // NOTE: The expected computed "_main-size" values for the flex items below
+ // appear to add up to more than their container's size, which would suggest
+ // that they overflow their container unnecessarily. But they don't actually
+ // overflow -- this discrepancy is simply because Gecko's code for reporting
+ // computed-sizes rounds to 6 significant figures (in particular, the method
+ // (nsTSubstring_CharT::AppendFloat() does this).  Internally, in app-units,
+ // the child frames' main-sizes add up exactly to the container's main-size,
+ // as you'd hope & expect.
+ {
+   container_properties:
+   {
+     "_main-size": "9000000px"
+   },
+   items:
+     [
+       {
+         "flex": "3000000",
+         "_main-size": [ null,  "3000000px" ]
+       },
+       {
+         "flex": "1",
+         "_main-size": [ null,  "1px" ]
+       },
+       {
+         "flex": "1",
+         "_main-size": [ null,  "1px" ]
+       },
+       {
+         "flex": "2999999",
+         // NOTE: Expected value is off slightly, from float error when
+         // resolving flexible lengths & when generating computed value string:
+         "_main-size": [ null,  "3000000px" ]
+       },
+       {
+         "flex": "2999998",
+         // NOTE: Expected value is off slightly, from float error when
+         // resolving flexible lengths & when generating computed value string:
+         "_main-size": [ null,  "3000000px" ]
+       },
+       {
+         "flex": "1",
+         "_main-size": [ null,  "1px", 0.2 ]
+       },
+     ]
+ },
+ // Same flex items as previous testcase, but now reordered such that the items
+ // with tiny flex weights are all listed last:
+ {
+   container_properties:
+   {
+     "_main-size": "9000000px"
+   },
+   items:
+     [
+       {
+         "flex": "3000000",
+         "_main-size": [ null,  "3000000px" ]
+       },
+       {
+         "flex": "2999999",
+         // NOTE: Expected value is off slightly, from float error when
+         // resolving flexible lengths & when generating computed value string:
+         "_main-size": [ null,  "3000000px" ]
+       },
+       {
+         "flex": "2999998",
+         // NOTE: Expected value is off slightly, from float error when
+         // resolving flexible lengths & when generating computed value string:
+         "_main-size": [ null,  "3000000px" ]
+       },
+       {
+         "flex": "1",
+         "_main-size": [ null,  "1px", 0.2 ]
+       },
+       {
+         "flex": "1",
+         "_main-size": [ null,  "1px", 0.2 ]
+       },
+       {
+         "flex": "1",
+         "_main-size": [ null,  "1px", 0.2 ]
+       },
+     ]
+ },
+ // Same flex items as previous testcase, but now reordered such that the items
+ // with tiny flex weights are all listed first:
+ {
+   container_properties:
+   {
+     "_main-size": "9000000px"
+   },
+   items:
+     [
+       {
+         "flex": "1",
+         // NOTE: Expected value is off slightly, from float error when
+         // resolving flexible lengths:
+         "_main-size": [ null,  "1px", 0.2 ]
+       },
+       {
+         "flex": "1",
+         // NOTE: Expected value is off slightly, from float error when
+         // resolving flexible lengths:
+         "_main-size": [ null,  "1px", 0.2 ]
+       },
+       {
+         "flex": "1",
+         // NOTE: Expected value is off slightly, from float error when
+         // resolving flexible lengths:
+         "_main-size": [ null,  "1px", 0.2 ]
+       },
+       {
+         "flex": "3000000",
+         "_main-size": [ null,  "3000000px" ]
+       },
+       {
+         "flex": "2999999",
+         // NOTE: Expected value is off slightly, from float error when
+         // resolving flexible lengths & when generating computed value string:
+         "_main-size": [ null,  "3000000px" ]
+       },
+       {
+         "flex": "2999998",
+         // NOTE: Expected value is off slightly, from float error when
+         // resolving flexible lengths & when generating computed value string:
+         "_main-size": [ null,  "3000000px" ]
+       },
+     ]
+ },
+
+ // Trying "flex: auto" (== "1 1 auto") w/ a mix of flex-grow/flex-basis values
+ {
+   items:
+     [
+       {
+         "flex": "auto",
+         "_main-size": [ null, "45px" ]
+       },
+       {
+         "flex": "2",
+         "_main-size": [ null, "90px" ]
+       },
+       {
+         "flex": "20px 1 0",
+         "_main-size": [ null, "65px" ]
+       }
+     ]
+ },
+ // Same as previous, but with items cycled & different syntax
+ {
+   items:
+     [
+       {
+         "flex": "20px",
+         "_main-size": [ null, "65px" ]
+       },
+       {
+         "flex": "1",
+         "_main-size": [ null, "45px" ]
+       },
+       {
+         "flex": "2",
+         "_main-size": [ null, "90px" ]
+       }
+     ]
+ },
+ {
+   items:
+     [
+       {
+         "flex": "2",
+         "_main-size": [ null,  "100px" ],
+         "border": "0px dashed",
+         "_border-main-start-width": [ "5px",  "5px" ],
+         "_border-main-end-width": [ "15px", "15px" ],
+         "_margin-main-start": [ "22px", "22px" ],
+         "_margin-main-end": [ "8px", "8px" ]
+       },
+       {
+         "flex": "1",
+         "_main-size": [ null,  "50px" ],
+         "_margin-main-start": [ "auto", "0px" ],
+         "_padding-main-end": [ "auto", "0px" ],
+       }
+     ]
+ },
+ // Test negative flexibility:
+
+ // Basic testcase: just 1 item (relying on initial "flex-shrink: 1") --
+ // should shrink to container size.
+ {
+   items:
+     [
+       { "_main-size": [ "400px",  "200px" ] },
+     ],
+ },
+ // ...and now with a "flex" specification and a different flex-shrink value:
+ {
+   items:
+     [
+       {
+         "flex": "4 2 250px",
+         "_main-size": [ null,  "200px" ]
+       },
+     ],
+ },
+ // ...and now with multiple items, which all shrink proportionally (by 50%)
+ // to fit to the container, since they have the same (initial) flex-shrink val
+ {
+   items:
+     [
+       { "_main-size": [ "80px",   "40px" ] },
+       { "_main-size": [ "40px",   "20px" ] },
+       { "_main-size": [ "30px",   "15px" ] },
+       { "_main-size": [ "250px", "125px" ] },
+     ]
+ },
+ // ...and now with positive flexibility specified. (should have no effect, so
+ // everything still shrinks by the same proportion, since the flex-shrink
+ // values are all the same).
+ {
+   items:
+     [
+       {
+         "flex": "4 3 100px",
+         "_main-size": [ null,  "80px" ]
+       },
+       {
+         "flex": "5 3 50px",
+         "_main-size": [ null,  "40px" ]
+       },
+       {
+         "flex": "0 3 100px",
+         "_main-size": [ null, "80px" ]
+       }
+     ]
+ },
+ // ...and now with *different* flex-shrink values:
+ {
+   items:
+     [
+       {
+         "flex": "4 2 50px",
+         "_main-size": [ null,  "30px" ]
+       },
+       {
+         "flex": "5 3 50px",
+         "_main-size": [ null,  "20px" ]
+       },
+       {
+         "flex": "0 0 150px",
+         "_main-size": [ null, "150px" ]
+       }
+     ]
+ },
+ // Same ratio as prev. testcase; making sure we handle float inaccuracy
+ {
+   items:
+     [
+       {
+         "flex": "4 20000000 50px",
+         "_main-size": [ null,  "30px" ]
+       },
+       {
+         "flex": "5 30000000 50px",
+         "_main-size": [ null,  "20px" ]
+       },
+       {
+         "flex": "0 0.0000001 150px",
+         "_main-size": [ null, "150px" ]
+       }
+     ]
+ },
+ // Another "different flex-shrink values" testcase:
+ {
+   items:
+     [
+       {
+         "flex": "4 2 115px",
+         "_main-size": [ null,  "69px" ]
+       },
+       {
+         "flex": "5 1 150px",
+         "_main-size": [ null,  "120px" ]
+       },
+       {
+         "flex": "1 4 30px",
+         "_main-size": [ null,  "6px" ]
+       },
+       {
+         "flex": "1 0 5px",
+         "_main-size": [ null, "5px" ]
+       },
+     ]
+ },
+
+ // ...and now with min-size (clamping the effects of flex-shrink on one item):
+ {
+   items:
+     [
+       {
+         "flex": "4 5 75px",
+         "_min-main-size": "50px",
+         "_main-size": [ null,  "50px" ],
+       },
+       {
+         "flex": "5 5 100px",
+         "_main-size": [ null,  "62.5px" ]
+       },
+       {
+         "flex": "0 4 125px",
+         "_main-size": [ null, "87.5px" ]
+       }
+     ]
+ },
+
+ // Test a min-size that's much larger than initial preferred size, but small
+ // enough that our flexed size pushes us over it:
+ {
+   items:
+     [
+       {
+         "flex": "auto",
+         "_min-main-size": "110px",
+         "_main-size": [ "50px",  "125px" ]
+       },
+       {
+         "flex": "auto",
+         "_main-size": [ null, "75px" ]
+       }
+     ]
+ },
+
+ // Test a min-size that's much larger than initial preferred size, and is
+ // even larger than our positively-flexed size, so that we have to increase it
+ // (as a 'min violation') after we've flexed.
+ {
+   items:
+     [
+       {
+         "flex": "auto",
+         "_min-main-size": "150px",
+         "_main-size": [ "50px",  "150px" ]
+       },
+       {
+         "flex": "auto",
+         "_main-size": [ null, "50px" ]
+       }
+     ]
+ },
+
+ // Test min-size on multiple items simultaneously:
+ {
+   items:
+     [
+       {
+         "flex": "auto",
+         "_min-main-size": "20px",
+         "_main-size": [ null,  "20px" ]
+       },
+       {
+         "flex": "9 auto",
+         "_min-main-size": "150px",
+         "_main-size": [ "50px",  "180px" ]
+       },
+     ]
+ },
+ {
+   items:
+     [
+       {
+         "flex": "1 1 0px",
+         "_min-main-size": "90px",
+         "_main-size": [ null, "90px" ]
+       },
+       {
+         "flex": "1 1 0px",
+         "_min-main-size": "80px",
+         "_main-size": [ null, "80px" ]
+       },
+       {
+         "flex": "1 1 40px",
+         "_main-size": [ null, "30px" ]
+       }
+     ]
+ },
+
+ // Test a case where _min-main-size will be violated on different items in
+ // successive iterations of the "resolve the flexible lengths" loop
+ {
+   items:
+     [
+       {
+         "flex": "1 2 100px",
+         "_min-main-size": "90px",
+         "_main-size": [ null, "90px" ]
+       },
+       {
+         "flex": "1 1 100px",
+         "_min-main-size": "70px",
+         "_main-size": [ null, "70px" ]
+       },
+       {
+         "flex": "1 1 100px",
+         "_main-size": [ null, "40px" ]
+       }
+     ]
+ },
+
+ // Test some cases that have a min-size violation on one item and a
+ // max-size violation on another:
+
+ // Here, both items initially grow to 100px. That violates both
+ // items' sizing constraints (it's smaller than the min-size and larger than
+ // the max-size), so we clamp both of them and sum the clamping-differences:
+ //
+ //   (130px - 100px) + (50px - 100px) = (30px) + (-50px) = -20px
+ //
+ // This sum is negative, so (per spec) we freeze the item that had its
+ // max-size violated (the second one) and restart the algorithm.  This time,
+ // all the available space (200px - 50px = 150px) goes to the not-yet-frozen
+ // first item, and that puts it above its min-size, so all is well.
+ {
+   items:
+     [
+       {
+         "flex": "auto",
+         "_min-main-size": "130px",
+         "_main-size": [ null, "150px" ]
+       },
+       {
+         "flex": "auto",
+         "_max-main-size": "50px",
+         "_main-size": [ null,  "50px" ]
+       },
+     ]
+ },
+
+ // As above, both items initially grow to 100px, and that violates both items'
+ // constraints. However, now the sum of the clamping differences is:
+ //
+ //   (130px - 100px) + (80px - 100px) = (30px) + (-20px) = 10px
+ //
+ // This sum is positive, so (per spec) we freeze the item that had its
+ // min-size violated (the first one) and restart the algorithm. This time,
+ // all the available space (200px - 130px = 70px) goes to the not-yet-frozen
+ // second item, and that puts it below its max-size, so all is well.
+ {
+   items:
+     [
+       {
+         "flex": "auto",
+         "_min-main-size": "130px",
+         "_main-size": [ null, "130px" ]
+       },
+       {
+         "flex": "auto",
+         "_max-main-size": "80px",
+         "_main-size": [ null,  "70px" ]
+       },
+     ]
+ },
+
+ // As above, both items initially grow to 100px, and that violates both items'
+ // constraints. So we clamp both items and sum the clamping differences to
+ // see what to do next.  The sum is:
+ //
+ //   (80px - 100px) + (120px - 100px) = (-20px) + (20px) = 0px
+ //
+ // Per spec, if the sum is 0, we're done -- we leave both items at their
+ // clamped sizes.
+ {
+   items:
+     [
+       {
+         "flex": "auto",
+         "_max-main-size": "80px",
+         "_main-size": [ null,  "80px" ]
+       },
+       {
+         "flex": "auto",
+         "_min-main-size": "120px",
+         "_main-size": [ null, "120px" ]
+       },
+     ]
+ },
+
+ // Test cases where flex-grow sums to less than 1:
+ // ===============================================
+ // This makes us treat the flexibilities like "fraction of free space"
+ // instead of weights, so that e.g. a single item with "flex-grow: 0.1"
+ // will only get 10% of the free space instead of all of the free space.
+
+ // Basic cases where flex-grow sum is less than 1:
+ {
+   items:
+     [
+       {
+         "flex": "0.1 100px",
+         "_main-size": [ null, "110px" ] // +10% of free space
+       },
+     ]
+ },
+ {
+   items:
+     [
+       {
+         "flex": "0.8 0px",
+         "_main-size": [ null, "160px" ] // +80% of free space
+       },
+     ]
+ },
+
+ // ... and now with two flex items:
+ {
+   items:
+     [
+       {
+         "flex": "0.4 70px",
+         "_main-size": [ null, "110px" ] // +40% of free space
+       },
+       {
+         "flex": "0.2 30px",
+         "_main-size": [ null,  "50px" ] // +20% of free space
+       },
+     ]
+ },
+
+ // ...and now with max-size modifying how much free space one item can take:
+ {
+   items:
+     [
+       {
+         "flex": "0.4 70px",
+         "_main-size": [ null, "110px" ] // +40% of free space
+       },
+       {
+         "flex": "0.2 30px",
+         "_max-main-size": "35px",
+         "_main-size": [ null,  "35px" ] // +20% free space, then clamped
+       },
+     ]
+ },
+ // ...and now with a max-size smaller than our flex-basis:
+ // (This makes us freeze the second item right away, before we compute
+ // the initial free space.)
+ {
+   items:
+     [
+       {
+         "flex": "0.4 70px",
+         "_main-size": [ null, "118px" ] // +40% of 200px-70px-10px
+       },
+       {
+         "flex": "0.2 30px",
+         "_max-main-size": "10px",
+         "_main-size": [ null,  "10px" ] // immediately frozen
+       },
+     ]
+ },
+ // ...and now with a max-size and a huge flex-basis, such that we initially
+ // have negative free space, which makes the "% of [original] free space"
+ // calculations a bit more subtle. We set the "original free space" after
+ // we've clamped the second item (the first time the free space is positive).
+ {
+   items:
+     [
+       {
+         "flex": "0.4 70px",
+         "_main-size": [ null, "118px" ] // +40% of free space _after freezing
+                                         // the other item_
+       },
+       {
+         "flex": "0.2 150px",
+         "_max-main-size": "10px",
+         "_main-size": [ null,  "10px" ] // clamped immediately
+       },
+     ]
+ },
+
+ // Now with min-size modifying how much free space our items take:
+ {
+   items:
+     [
+       {
+         "flex": "0.4 70px",
+         "_main-size": [ null, "110px" ] // +40% of free space
+       },
+       {
+         "flex": "0.2 30px",
+         "_min-main-size": "70px",
+         "_main-size": [ null,  "70px" ] // +20% free space, then clamped
+       },
+     ]
+ },
+
+ // ...and now with a large enough min-size that it prevents the other flex
+ // item from taking its full desired portion of the original free space:
+ {
+   items:
+     [
+       {
+         "flex": "0.4 70px",
+         "_main-size": [ null, "80px" ] // (Can't take my full +40% of
+                                        // free space due to other item's
+                                        // large min-size.)
+       },
+       {
+         "flex": "0.2 30px",
+         "_min-main-size": "120px",
+         "_main-size": [ null,  "120px" ] // +20% free space, then clamped
+       },
+     ]
+ },
+ // ...and now with a large-enough min-size that it pushes the other flex item
+ // to actually shrink a bit (with default "flex-shrink:1"):
+ {
+   items:
+     [
+       {
+         "flex": "0.3 30px",
+         "_main-size": [ null,  "20px" ] // -10px, instead of desired +45px
+       },
+       {
+         "flex": "0.2 20px",
+         "_min-main-size": "180px",
+         "_main-size": [ null,  "180px" ] // +160px, instead of desired +30px
+       },
+     ]
+ },
+
+ // In this case, the items' flexibilities don't initially sum to < 1, but they
+ // do after we freeze the third item for violating its max-size.
+ {
+   items:
+     [
+       {
+         "flex": "0.3 30px",
+         "_main-size": [ null,  "75px" ]
+         // 1st loop: desires (0.3 / 5) * 150px = 9px. Tentatively granted.
+         // 2nd loop: desires 0.3 * 150px = 45px. Tentatively granted.
+         // 3rd loop: desires 0.3 * 150px = 45px. Granted +45px.
+       },
+       {
+         "flex": "0.2 20px",
+         "_max-main-size": "30px",
+         "_main-size": [ null,  "30px" ]
+         // First loop: desires (0.2 / 5) * 150px = 6px. Tentatively granted.
+         // Second loop: desires 0.2 * 150px = 30px. Frozen at +10px.
+       },
+       {
+         "flex": "4.5 0px",
+         "_max-main-size": "20px",
+         "_main-size": [ null,  "20px" ]
+         // First loop: desires (4.5 / 5) * 150px = 135px. Frozen at +20px.
+       },
+     ]
+ },
+
+ // Make sure we calculate "original free space" correctly when one of our
+ // flex items will be clamped right away, due to max-size preventing it from
+ // growing at all:
+ {
+   // Here, the second flex item is effectively inflexible; it's
+   // immediately frozen at 40px since we're growing & this item's max size
+   // trivially prevents it from growing. This leaves us with an "original
+   // free space" of 60px. The first flex item takes half of that, due to
+   // its flex-grow value of 0.5.
+   items:
+     [
+       {
+         "flex": "0.5 100px",
+         "_main-size": [ null,  "130px" ]
+       },
+       {
+         "flex": "1 98px",
+         "_max-main-size": "40px",
+         "_main-size": [ null,  "40px" ]
+       },
+     ]
+ },
+ {
+   // Same as previous example, but with a larger flex-basis on the second
+   // element (which shouldn't ultimately matter, because its max size clamps
+   // its size immediately anyway).
+   items:
+     [
+       {
+         "flex": "0.5 100px",
+         "_main-size": [ null,  "130px" ]
+       },
+       {
+         "flex": "1 101px",
+         "_max-main-size": "40px",
+         "_main-size": [ null,  "40px" ]
+       },
+     ]
+ },
+
+ {
+   // Here, the third flex item is effectively inflexible; it's immediately
+   // frozen at 0px since we're growing & this item's max size trivially
+   // prevents it from growing. This leaves us with an "original free space" of
+   // 100px. The first flex item takes 40px, and the third takes 50px, due to
+   // their flex values of 0.4 and 0.5.
+   items:
+     [
+       {
+         "flex": "0.4 50px",
+         "_main-size": [ null,  "90px" ]
+       },
+       {
+         "flex": "0.5 50px",
+         "_main-size": [ null,  "100px" ]
+       },
+       {
+         "flex": "0 90px",
+         "_max-main-size": "0px",
+         "_main-size": [ null,  "0px" ]
+       },
+     ]
+ },
+ {
+   // Same as previous example, but with slightly larger flex-grow values on
+   // the first and second items, which sum to 1.0 and produce slightly larger
+   // main sizes. This demonstrates that there's no discontinuity between the
+   // "< 1.0 sum" to ">= 1.0 sum" behavior, in this situation at least.
+   items:
+     [
+       {
+         "flex": "0.45 50px",
+         "_main-size": [ null,  "95px" ]
+       },
+       {
+         "flex": "0.55 50px",
+         "_main-size": [ null,  "105px" ]
+       },
+       {
+         "flex": "0 90px",
+         "_max-main-size": "0px",
+         "_main-size": [ null,  "0px" ]
+       },
+     ]
+ },
+
+ // Test cases where flex-shrink sums to less than 1:
+ // =================================================
+ // This makes us treat the flexibilities more like "fraction of (negative)
+ // free space" instead of weights, so that e.g. a single item with
+ // "flex-shrink: 0.1" will only shrink by 10% of amount that it overflows
+ // its container by.
+ //
+ // It gets a bit more complex when there are multiple flex items, because
+ // flex-shrink is scaled by the flex-basis before it's used as a weight. But
+ // even with that scaling, the general principal is that e.g. if the
+ // flex-shrink values *sum* to 0.6, then the items will collectively only
+ // shrink by 60% (and hence will still overflow).
+
+ // Basic cases where flex-grow sum is less than 1:
+ {
+   items:
+     [
+       {
+         "flex": "0 0.1 300px",
+         "_main-size": [ null,  "290px" ] // +10% of (negative) free space
+       },
+     ]
+ },
+ {
+   items:
+     [
+       {
+         "flex": "0 0.8 400px",
+         "_main-size": [ null,  "240px" ] // +80% of (negative) free space
+       },
+     ]
+ },
+
+ // ...now with two flex items, with the same flex-basis value:
+ {
+   items:
+     [
+       {
+         "flex": "0 0.4 150px",
+         "_main-size": [ null,  "110px" ] // +40% of (negative) free space
+       },
+       {
+         "flex": "0 0.2 150px",
+         "_main-size": [ null,  "130px" ] // +20% of (negative) free space
+       },
+     ]
+ },
+
+ // ...now with two flex items, with different flex-basis values (and hence
+ // differently-scaled flex factors):
+ {
+   items:
+     [
+       {
+         "flex": "0 0.3 100px",
+         "_main-size": [ null,  "76px" ]
+       },
+       {
+         "flex": "0 0.1 200px",
+         "_main-size": [ null,  "184px" ]
+       }
+     ]
+     // Notes:
+     //  - Free space: -100px
+     //  - Sum of flex-shrink factors: 0.3 + 0.1 = 0.4
+     //  - Since that sum ^ is < 1, we'll only distribute that fraction of
+     //    the free space. We'll distribute: -100px * 0.4 = -40px
+     //
+     //  - 1st item's scaled flex factor:  0.3 * 100px = 30
+     //  - 2nd item's scaled flex factor:  0.1 * 200px = 20
+     //  - 1st item's share of distributed free space: 30/(30+20) = 60%
+     //  - 2nd item's share of distributed free space: 20/(30+20) = 40%
+     //
+     // SO:
+     //  - 1st item gets 60% * -40px = -24px.  100px-24px = 76px
+     //  - 2nd item gets 40% * -40px = -16px.  200px-16px = 184px
+ },
+
+ // ...now with min-size modifying how much one item can shrink:
+ {
+   items:
+     [
+       {
+         "flex": "0 0.3 100px",
+         "_main-size": [ null,  "70px" ]
+       },
+       {
+         "flex": "0 0.1 200px",
+         "_min-main-size": "190px",
+         "_main-size": [ null,  "190px" ]
+       }
+     ]
+     // Notes:
+     //  - We proceed as in previous testcase, but clamp the second flex item
+     //    at its min main size.
+     //  - After that point, we have a total flex-shrink of = 0.3, so we
+     //    distribute 0.3 * -100px = -30px to the remaining unfrozen flex
+     //    items. Since there's only one unfrozen item left, it gets all of it.
+ },
+
+ // ...now with min-size larger than our flex-basis:
+ // (This makes us freeze the second item right away, before we compute
+ // the initial free space.)
+ {
+   items:
+     [
+       {
+         "flex": "0 0.3 100px",
+         "_main-size": [ null,  "55px" ] // +30% of 200px-100px-250px
+       },
+       {
+         "flex": "0 0.1 200px",
+         "_min-main-size": "250px",
+         "_main-size": [ null,  "250px" ] // immediately frozen
+       }
+     ]
+     // (Same as previous example, except the min-main-size prevents the
+     // second item from shrinking at all)
+ },
+
+ // ...and now with a min-size and a small flex-basis, such that we initially
+ // have positive free space, which makes the "% of [original] free space"
+ // calculations a bit more subtle. We set the "original free space" after
+ // we've clamped the second item (the first time the free space is negative).
+ {
+   items:
+     [
+       {
+         "flex": "0 0.3 100px",
+         "_main-size": [ null,  "70px" ]
+       },
+       {
+         "flex": "0 0.1 50px",
+         "_min-main-size": "200px",
+         "_main-size": [ null,  "200px" ]
+       }
+     ]
+ },
+
+ // Now with max-size making an item shrink more than its flex-shrink value
+ // calls for:
+ {
+   items:
+     [
+       {
+         "flex": "0 0.3 100px",
+         "_main-size": [ null,  "70px" ]
+       },
+       {
+         "flex": "0 0.1 200px",
+         "_max-main-size": "150px",
+         "_main-size": [ null,  "150px" ]
+       }
+     ]
+     // Notes:
+     //  - We proceed as in an earlier testcase, but clamp the second flex item
+     //    at its max main size.
+     //  - After that point, we have a total flex-shrink of = 0.3, so we
+     //    distribute 0.3 * -100px = -30px to the remaining unfrozen flex
+     //    items. Since there's only one unfrozen item left, it gets all of it.
+ },
+
+ // ...and now with a small enough max-size that it prevents the other flex
+ // item from taking its full desired portion of the (negative) original free
+ // space:
+ {
+   items:
+     [
+       {
+         "flex": "0 0.3 100px",
+         "_main-size": [ null,  "90px" ]
+       },
+       {
+         "flex": "0 0.1 200px",
+         "_max-main-size": "110px",
+         "_main-size": [ null,  "110px" ]
+       }
+     ]
+     // Notes:
+     //  - We proceed as in an earlier testcase, but clamp the second flex item
+     //    at its max main size.
+     //  - After that point, we have a total flex-shrink of 0.3, which would
+     //    have us distribute 0.3 * -100px = -30px to the (one) remaining
+     //    unfrozen flex item. But our remaining free space is only -10px at
+     //    that point, so we distribute that instead.
+ },
+
+ // ...and now with a small enough max-size that it pushes the other flex item
+ // to actually grow a bit (with custom "flex-grow: 1" for this testcase):
+ {
+   items:
+     [
+       {
+         "flex": "1 0.3 100px",
+         "_main-size": [ null,  "120px" ]
+       },
+       {
+         "flex": "1 0.1 200px",
+         "_max-main-size": "80px",
+         "_main-size": [ null,  "80px" ]
+       }
+     ]
+ },
+
+ // In this case, the items' flexibilities don't initially sum to < 1, but they
+ // do after we freeze the third item for violating its min-size.
+ {
+   items:
+     [
+       {
+         "flex": "0 0.3 100px",
+         "_main-size": [ null,  "76px" ]
+       },
+       {
+         "flex": "0 0.1 150px",
+         "_main-size": [ null,  "138px" ]
+       },
+       {
+         "flex": "0 0.8 10px",
+         "_min-main-size": "40px",
+         "_main-size": [ null,  "40px" ]
+       }
+     ]
+     // Notes:
+     //  - We immediately freeze the 3rd item, since we're shrinking and its
+     //    min size obviously prevents it from shrinking at all.  This leaves
+     //    200px - 100px - 150px - 40px = -90px of "initial free space".
+     //
+     //  - Our remaining flexible items have a total flex-shrink of 0.4,
+     //    so we can distribute a total of 0.4 * -90px = -36px
+     //
+     //  - We distribute that space using *scaled* flex factors:
+     //    * 1st item's scaled flex factor:  0.3 * 100px = 30
+     //    * 2nd item's scaled flex factor:  0.1 * 150px = 15
+     //   ...which means...
+     //    * 1st item's share of distributed free space: 30/(30+15) = 2/3
+     //    * 2nd item's share of distributed free space: 15/(30+15) = 1/3
+     //
+     // SO:
+     //  - 1st item gets 2/3 * -36px = -24px. 100px - 24px = 76px
+     //  - 2nd item gets 1/3 * -36px = -12px. 150px - 12px = 138px
+ },
+
+ // In this case, the items' flexibilities sum to > 1, in part due to an item
+ // that *can't actually shrink* due to its 0 flex-basis (which gives it a
+ // "scaled flex factor" of 0). This prevents us from triggering the special
+ // behavior for flexibilities that sum to less than 1, and as a result, the
+ // first item ends up absorbing all of the free space.
+ {
+   items:
+     [
+       {
+         "flex": "0 .5 300px",
+         "_main-size": [ null,  "200px" ]
+       },
+       {
+         "flex": "0 5 0px",
+         "_main-size": [ null,  "0px" ]
+       }
+     ]
+ },
+
+ // This case is similar to the one above, but with a *barely* nonzero base
+ // size for the second item. This should produce a result similar to the case
+ // above. (In particular, we should first distribute a very small amount of
+ // negative free space to the second item, getting it to approximately zero,
+ // and distribute the bulk of the negative free space to the first item,
+ // getting it to approximately 200px.)
+ {
+   items:
+     [
+       {
+         "flex": "0 .5 300px",
+         "_main-size": [ null,  "200px" ]
+       },
+       {
+         "flex": "0 1 0.01px",
+         "_main-size": [ null,  "0px" ]
+       }
+     ]
+ },
+ // This case is similar to the ones above, but now we've increased the
+ // flex-shrink value on the second-item so that it claims enough of the
+ // negative free space to go below its min-size (0px). So, it triggers a min
+ // violation & is frozen. For the loop *after* the min violation, the sum of
+ // the remaining flex items' flex-shrink values is less than 1, so we trigger
+ // the special <1 behavior and only distribute half of the remaining
+ // (negative) free space to the first item (instead of all of it).
+ {
+   items:
+     [
+       {
+         "flex": "0 .5 300px",
+         "_main-size": [ null,  "250px" ]
+       },
+       {
+         "flex": "0 5 0.01px",
+         "_main-size": [ null,  "0px" ]
+       }
+     ]
+ },
+];