[meson] Add first regression test to FreeType

* tests/README.md: documentation explaining how to
  build and run the tests with the Meson build.

* tests/scripts/download-test-fonts.sh: Simple script
  to download test font files to the 'tests/data/'
  folder.

* meson.build, meson_options.txt, tests/meson.build:
  Add 'tests' option to enable building and running the
  test programs, disabled by default.

* tests/issue-1063/main.c: Simple regression test to
  exhibit issue 1063.

* .gitignore: Ignore the content of the tests/data/
  folder for now.

7 files changed, 136 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index 6e9fd98ea..e4f1510bf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@ include/dlg/
 src/dlg/dlg.c
 subprojects/*
 !subprojects/*.wrap
+/tests/data/*
diff --git a/meson.build b/meson.build
index c5529a655..152024de0 100644
--- a/meson.build
+++ b/meson.build
@@ -369,6 +369,9 @@ pkgconfig.generate(ft2_lib,
   version: ft2_pkgconfig_version,
 )
 
+if get_option('tests').enabled()
+  subdir('tests')
+endif
 
 # NOTE: Unlike the old `make refdoc` command, this generates the
 # documentation under `$BUILD/docs/` since Meson doesn't support modifying
diff --git a/meson_options.txt b/meson_options.txt
index f0fc50a38..8747f52df 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -35,6 +35,11 @@ option('harfbuzz',
                + ' If available, many glyphs not directly addressable'
                + ' by a font\'s character map will be hinted also.')
 
+option('tests',
+  type: 'feature',
+  value: 'disabled',
+  description: 'Enable FreeType unit and regression tests.')
+
 option('brotli',
   type: 'feature',
   value: 'auto',
diff --git a/tests/README.md b/tests/README.md
new file mode 100644
index 000000000..f6f861182
--- /dev/null
+++ b/tests/README.md
@@ -0,0 +1,22 @@
+# Unit and regression tests for the FreeType library
+
+## Quick Start
+
+### Download test fonts
+
+Run the `tests/scripts/download-fonts.sh` script, which will
+download test fonts to the `tests/data/` directory first.
+
+### Build the test programs
+
+The tests are only built with the Meson build system, and
+are disabled by default, enable the 'tests' option to compile
+them, as in:
+
+  meson setup out -Dtests=enabled
+  meson compile -C out
+
+### Run the test programs
+
+  meson test -C out
+
diff --git a/tests/issue-1063/main.c b/tests/issue-1063/main.c
new file mode 100644
index 000000000..eac02642a
--- /dev/null
+++ b/tests/issue-1063/main.c
@@ -0,0 +1,32 @@
+#include <stdio.h>
+
+#include <freetype/freetype.h>
+#include <ft2build.h>
+
+int
+main( void )
+{
+  FT_Library library;
+  FT_Face    face;
+
+  /* Assumes this is run from out/ build directory though 'meson test -C out' */
+  const char* filepath = "../tests/data/As.I.Lay.Dying.ttf";
+
+  FT_Init_FreeType( &library );
+  FT_New_Face( library, filepath, 0, &face );
+  if ( !face )
+  {
+    fprintf( stderr, "Could not open file: %s\n", filepath );
+    return 1;
+  }
+
+  for ( FT_ULong i = 59; i < 171; i++ )
+  {
+    FT_UInt  gid  = FT_Get_Char_Index( face, i );
+    FT_Error code = FT_Load_Glyph( face, gid, FT_LOAD_DEFAULT );
+    if ( code )
+      printf( "unknown %d for char %lu, gid %u\n", code, i, gid );
+  }
+
+  return 0;
+}
diff --git a/tests/meson.build b/tests/meson.build
new file mode 100644
index 000000000..8c5d0345f
--- /dev/null
+++ b/tests/meson.build
@@ -0,0 +1,7 @@
+test_issue_1063 = executable('issue-1063',
+  files([ 'issue-1063/main.c' ]),
+  dependencies: freetype_dep,
+)
+
+test('issue-1063', test_issue_1063, suite: 'regression')
+
diff --git a/tests/scripts/download-test-fonts.sh b/tests/scripts/download-test-fonts.sh
new file mode 100755
index 000000000..1158f10c5
--- /dev/null
+++ b/tests/scripts/download-test-fonts.sh
@@ -0,0 +1,66 @@
+#!/usr/bin/bash
+# Download test fonts used by the FreeType regression test programs.
+# These will be copied to $FREETYPE/tests/data/
+# Each font file contains an 8-hexchar prefix corresponding to its md5sum
+
+set -e
+
+export LANG=C
+export LC_ALL=C
+
+PROGDIR=$(dirname "$0")
+PROGNAME=$(basename "$0")
+
+# Download a file from a given URL
+#
+# $1: URL
+# $2: Destination directory
+# $3: If not empty, destination file name. Default is to take
+# the URL's basename.
+#
+download_file () {
+  local URL=$1
+  local DST_DIR=$2
+  local DST_FILE=$3
+  if [[ -z "$DST_FILE" ]]; then
+    DST_FILE=$(basename "$URL")
+  fi
+  echo "URL: $URL"
+  wget -q -O "$DST_DIR/$DST_FILE" "$URL"
+}
+
+# $1: URL
+# $2: Destination directory
+# $3+: Optional file list, otherwise the full archive is extracted to $2
+download_and_extract_zip () {
+  local URL=$1
+  local DST_DIR=$2
+  shift
+  shift
+  TEMP_DST_DIR=$(mktemp -d)
+  TEMP_DST_NAME="a.zip"
+  download_file "$URL" "$TEMP_DST_DIR" "$TEMP_DST_NAME"
+  unzip -qo "$TEMP_DST_DIR/$TEMP_DST_NAME" -d "$DST_DIR" "$@"
+  rm -rf "$TEMP_DST_DIR"
+}
+
+# $1: File path
+# $2: Expected md5sum
+md5sum_check () {
+  local FILE=$1
+  local EXPECTED=$2
+  local HASH=$(md5sum "$FILE" | cut -d" " -f1)
+  if [[ "$EXPECTED" != "$HASH" ]]; then
+    echo "$FILE: Invalid md5sum $HASH expected $EXPECTED"
+    return 1
+  fi
+}
+
+INSTALL_DIR=$(cd $PROGDIR/.. && pwd)/data
+
+mkdir -p "$INSTALL_DIR"
+
+# See https://gitlab.freedesktop.org/freetype/freetype/-/issues/1063
+download_and_extract_zip "https://github.com/python-pillow/Pillow/files/6622147/As.I.Lay.Dying.zip" "$INSTALL_DIR"
+mv "$INSTALL_DIR/As I Lay Dying.ttf" "$INSTALL_DIR/As.I.Lay.Dying.ttf"
+md5sum_check "$INSTALL_DIR/As.I.Lay.Dying.ttf" e153d60e66199660f7cfe99ef4705ad7