#!/bin/bash
#
# Copyright 2015 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Common utility file for Bazel shell tests
#
# unittest.bash: a unit test framework in Bash.
#
# A typical test suite looks like so:
#
#   ------------------------------------------------------------------------
#   #!/bin/bash
#
#   source path/to/unittest.bash || exit 1
#
#   # Test that foo works.
#   function test_foo() {
#     foo >$TEST_log || fail "foo failed";
#     expect_log "blah" "Expected to see 'blah' in output of 'foo'."
#   }
#
#   # Test that bar works.
#   function test_bar() {
#     bar 2>$TEST_log || fail "bar failed";
#     expect_not_log "ERROR" "Unexpected error from 'bar'."
#     ...
#     assert_equals $x $y
#   }
#
#   run_suite "Test suite for blah"
#   ------------------------------------------------------------------------
#
# Each test function is considered to pass iff fail() is not called
# while it is active.  fail() may be called directly, or indirectly
# via other assertions such as expect_log().  run_suite must be called
# at the very end.
#
# A test suite may redefine functions "set_up" and/or "tear_down";
# these functions are executed before and after each test function,
# respectively.  Similarly, "cleanup" and "timeout" may be redefined,
# and these function are called upon exit (of any kind) or a timeout.
#
# The user can pass --test_filter to blaze test to select specific tests
# to run with Bash globs. A union of tests matching any of the provided globs
# will be run. Additionally the user may define TESTS=(test_foo test_bar ...) to
# specify a subset of test functions to execute, for example, a working set
# during debugging. By default, all functions called test_* will be executed.
#
# This file provides utilities for assertions over the output of a
# command.  The output of the command under test is directed to the
# file $TEST_log, and then the expect_log* assertions can be used to
# test for the presence of certain regular expressions in that file.
#
# The test framework is responsible for restoring the original working
# directory before each test.
#
# The order in which test functions are run is not defined, so it is
# important that tests clean up after themselves.
#
# Each test will be run in a new subshell.
#
# Functions named __* are not intended for use by clients.
#
# This framework implements the "test sharding protocol".
#

[[ -n "$BASH_VERSION" ]] ||
  { echo "unittest.bash only works with bash!" >&2; exit 1; }

export BAZEL_SHELL_TEST=1

DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)

# Load the environment support utilities.
source "${DIR}/unittest_utils.sh" || { echo "unittest_utils.sh not found" >&2; exit 1; }

#### Global variables:

TEST_name=""                    # The name of the current test.

TEST_log=$TEST_TMPDIR/log       # The log file over which the
                                # expect_log* assertions work.  Must
                                # be absolute to be robust against
                                # tests invoking 'cd'!

TEST_passed="true"              # The result of the current test;
                                # failed assertions cause this to
                                # become false.

# These variables may be overridden by the test suite:

TESTS=()                        # A subset or "working set" of test
                                # functions that should be run.  By
                                # default, all tests called test_* are
                                # run.

_TEST_FILTERS=()                # List of globs to use to filter the tests.
                                # If non-empty, all tests matching at least one
                                # of the globs are run and test list provided in
                                # the arguments is ignored if present.

__in_tear_down=0                # Indicates whether we are in `tear_down` phase
                                # of test. Used to avoid re-entering `tear_down`
                                # on failures within it.

# These variables are used for handling test shards that are manually defined
# via the define_test_shard() function.

_test_shards=()                 # Array of overall test shards. Each array
                                # element is a string containing the names of
                                # the test methods in the shard, separated by
                                # spaces.

_test_shard_count=0             # Number of overall test shards.

_manual_test_shards=()          # Array of manually defined test shards.

_manual_test_shard_count=0      # Number of manual test shards.

_manual_sharded_bool_prefix="_manual_sharded_bool_"  # Prefix for bool variables
                                # that mark whether a test method is manually
                                # sharded. The actual bool variables are named
                                # like <prefix><test_method> and are set using
                                # printf -v. This is used because bash 3.2
                                # (MacOS) doesn't support associative arrays.

if (( $# > 0 )); then
  (
    IFS=':'
    echo "WARNING: Passing test names in arguments (--test_arg) is deprecated, please use --test_filter='$*' instead." >&2
  )

  # Legacy behavior is to ignore missing regexp, but with errexit
  # the following line fails without || true.
  # TODO(dmarting): maybe we should revisit the way of selecting
  # test with that framework (use Bazel's environment variable instead).
  TESTS=($(for i in "$@"; do echo $i; done | grep ^test_ || true))
  if (( ${#TESTS[@]} == 0 )); then
    echo "WARNING: Arguments do not specify tests!" >&2
  fi
fi
# TESTBRIDGE_TEST_ONLY contains the value of --test_filter, if any. We want to
# preferentially use that instead of $@ to determine which tests to run.
if [[ ${TESTBRIDGE_TEST_ONLY:-} != "" ]]; then
  if (( ${#TESTS[@]} != 0 )); then
    echo "WARNING: Both --test_arg and --test_filter specified, ignoring --test_arg" >&2
    TESTS=()
  fi
  # Split TESTBRIDGE_TEST_ONLY on colon and store it in `_TEST_FILTERS` array.
  IFS=':' read -r -a _TEST_FILTERS <<< "$TESTBRIDGE_TEST_ONLY"
fi

TEST_verbose="true"             # Whether or not to be verbose.  A
                                # command; "true" or "false" are
                                # acceptable.  The default is: true.

TEST_script="$0"                # Full path to test script
# Check if the script path is absolute, if not prefix the PWD.
if [[ ! "$TEST_script" = /* ]]; then
  TEST_script="${PWD}/$0"
fi


#### Internal functions

function __show_log() {
    echo "-- Test log: -----------------------------------------------------------"
    [[ -e $TEST_log ]] && cat "$TEST_log" || echo "(Log file did not exist.)"
    echo "------------------------------------------------------------------------"
}

# Usage: __pad <title> <pad-char>
# Print $title padded to 80 columns with $pad_char.
function __pad() {
    local title=$1
    local pad=$2
    # Ignore the subshell error -- `head` closes the fd before reading to the
    # end, therefore the subshell will get SIGPIPE while stuck in `write`.
    {
        echo -n "${pad}${pad} ${title} "
        printf "%80s" " " | tr ' ' "$pad"
    } | head -c 80 || true
    echo
}

#### Exported functions

# Usage: init_test ...
# Deprecated.  Has no effect.
function init_test() {
    :
}


# Usage: set_up
# Called before every test function.  May be redefined by the test suite.
function set_up() {
    :
}

# Usage: tear_down
# Called after every test function.  May be redefined by the test suite.
function tear_down() {
    :
}

# Usage: cleanup
# Called upon eventual exit of the test suite.  May be redefined by
# the test suite.
function cleanup() {
    :
}

# Usage: timeout
# Called upon early exit from a test due to timeout.
function timeout() {
    :
}

# Usage: testenv_set_up
# Called prior to set_up. For use by testenv.sh.
function testenv_set_up() {
    :
}

# Usage: testenv_tear_down
# Called after tear_down. For use by testenv.sh.
function testenv_tear_down() {
    :
}

# Usage: fail <message> [<message> ...]
# Print failure message with context information, and mark the test as
# a failure.  The context includes a stacktrace including the longest sequence
# of calls outside this module.  (We exclude the top and bottom portions of
# the stack because they just add noise.)  Also prints the contents of
# $TEST_log.
function fail() {
    __show_log >&2
    echo "${TEST_name} FAILED: $*." >&2
    # Keep the original error message if we fail in `tear_down` after a failure.
    [[ "${TEST_passed}" == "true" ]] && echo "$@" >"$TEST_TMPDIR"/__fail
    TEST_passed="false"
    __show_stack
    # Cleanup as we are leaving the subshell now
    __run_tear_down_after_failure
    exit 1
}

function __run_tear_down_after_failure() {
    # Skip `tear_down` after a failure in `tear_down` to prevent infinite
    # recursion.
    (( __in_tear_down )) && return
    __in_tear_down=1
    echo -e "\nTear down:\n" >&2
    tear_down
    testenv_tear_down
}

# Usage: warn <message>
# Print a test warning with context information.
# The context includes a stacktrace including the longest sequence
# of calls outside this module.  (We exclude the top and bottom portions of
# the stack because they just add noise.)
function warn() {
    __show_log >&2
    echo "${TEST_name} WARNING: $1." >&2
    __show_stack

    if [[ -n "${TEST_WARNINGS_OUTPUT_FILE:-}" ]]; then
      echo "${TEST_name} WARNING: $1." >> "$TEST_WARNINGS_OUTPUT_FILE"
    fi
}

# Usage: show_stack
# Prints the portion of the stack that does not belong to this module,
# i.e. the user's code that called a failing assertion.  Stack may not
# be available if Bash is reading commands from stdin; an error is
# printed in that case.
__show_stack() {
    local i=0
    local trace_found=0

    # Skip over active calls within this module:
    while (( i < ${#FUNCNAME[@]} )) && [[ ${BASH_SOURCE[i]:-} == "${BASH_SOURCE[0]}" ]]; do
       (( ++i ))
    done

    # Show all calls until the next one within this module (typically run_suite):
    while (( i < ${#FUNCNAME[@]} )) && [[ ${BASH_SOURCE[i]:-} != "${BASH_SOURCE[0]}" ]]; do
        # Read online docs for BASH_LINENO to understand the strange offset.
        # Undefined can occur in the BASH_SOURCE stack apparently when one exits from a subshell
        echo "${BASH_SOURCE[i]:-"Unknown"}:${BASH_LINENO[i - 1]:-"Unknown"}: in call to ${FUNCNAME[i]:-"Unknown"}" >&2
        (( ++i ))
        trace_found=1
    done

    (( trace_found )) || echo "[Stack trace not available]" >&2
}

# Usage: expect_log <regexp> [error-message]
# Asserts that $TEST_log matches regexp.  On failure prints the specified
# (optional) error message, and returns non-zero.
function expect_log() {
    local pattern=$1
    local message=${2:-"Expected regexp '$pattern' not found"}
    grep -sq -- "$pattern" $TEST_log && return 0

    fail "$message"
    return 1
}

# Usage: expect_log_warn <regexp> [error-message]
# Warns if $TEST_log does not match regexp.  On failure prints the specified
# (optional) warning message, and returns non-zero.
function expect_log_warn() {
    local pattern=$1
    local message=${2:-"Expected regexp '$pattern' not found"}
    grep -sq -- "$pattern" $TEST_log && return 0

    warn "$message"
    return 1
}

# Usage: expect_log_once <regexp> [error-message]
# Asserts that $TEST_log contains one line matching <regexp>.
# On failure prints the specified (optional) error message, and returns
# non-zero.
function expect_log_once() {
    local pattern=$1
    local message=${2:-"Expected regexp '$pattern' not found exactly once"}
    expect_log_n "$pattern" 1 "$message"
}

# Usage: expect_log_n <regexp> <count> [error-message]
# Asserts that $TEST_log contains <count> lines matching <regexp>.
# On failure prints the specified (optional) error message, and returns
# non-zero.
function expect_log_n() {
    local pattern=$1
    local expectednum=${2:-1}
    local message=${3:-"Expected regexp '$pattern' not found exactly $expectednum times"}
    local count=$(grep -sc -- "$pattern" $TEST_log)
    (( count == expectednum )) && return 0
    fail "$message (found $count times instead)"
    return 1
}

# Usage: expect_not_log <regexp> [error-message]
# Asserts that $TEST_log does not match regexp.
# On failure prints the specified (optional) error message, and returns
# non-zero.
function expect_not_log() {
    local pattern=$1
    local message=${2:-"Unexpected regexp '$pattern' found"}
    grep -sq -- "$pattern" $TEST_log || return 0

    fail "$message"
    return 1
}

# Usage: expect_query_targets <arguments>
# Checks that log file contains exactly the targets in the argument list.
function expect_query_targets() {
  for arg in "$@"; do
    expect_log_once "^$arg$"
  done

# Checks that the number of lines started with '//' equals to the number of
# arguments provided.
  expect_log_n "^//[^ ]*$" $#
}

# Usage: expect_log_with_timeout <regexp> <timeout> [error-message]
# Waits for the given regexp in the $TEST_log for up to timeout seconds.
# On failure prints the specified (optional) error message, and returns
# non-zero.
function expect_log_with_timeout() {
    local pattern=$1
    local timeout=$2
    local message=${3:-"Regexp '$pattern' not found in $timeout seconds"}
    local count=0
    while (( count < timeout )); do
      grep -sq -- "$pattern" "$TEST_log" && return 0
      let count=count+1
      sleep 1
    done

    grep -sq -- "$pattern" "$TEST_log" && return 0
    fail "$message"
    return 1
}

# Usage: expect_cmd_with_timeout <expected> <cmd> [timeout]
# Repeats the command once a second for up to timeout seconds (10s by default),
# until the output matches the expected value. Fails and returns 1 if
# the command does not return the expected value in the end.
function expect_cmd_with_timeout() {
    local expected="$1"
    local cmd="$2"
    local timeout=${3:-10}
    local count=0
    while (( count < timeout )); do
      local actual="$($cmd)"
      [[ "$expected" == "$actual" ]] && return 0
      (( ++count ))
      sleep 1
    done

    [[ "$expected" == "$actual" ]] && return 0
    fail "Expected '${expected}' within ${timeout}s, was '${actual}'"
    return 1
}

# Usage: assert_one_of <expected_list>... <actual>
# Asserts that actual is one of the items in expected_list
#
# Example:
#     local expected=( "foo", "bar", "baz" )
#     assert_one_of $expected $actual
function assert_one_of() {
    local args=("$@")
    local last_arg_index=$((${#args[@]} - 1))
    local actual=${args[last_arg_index]}
    unset args[last_arg_index]
    for expected_item in "${args[@]}"; do
      [[ "$expected_item" == "$actual" ]] && return 0
    done;

    fail "Expected one of '${args[*]}', was '$actual'"
    return 1
}

# Usage: assert_not_one_of <expected_list>... <actual>
# Asserts that actual is not one of the items in expected_list
#
# Example:
#     local unexpected=( "foo", "bar", "baz" )
#     assert_not_one_of $unexpected $actual
function assert_not_one_of() {
    local args=("$@")
    local last_arg_index=$((${#args[@]} - 1))
    local actual=${args[last_arg_index]}
    unset args[last_arg_index]
    for expected_item in "${args[@]}"; do
      if [[ "$expected_item" == "$actual" ]]; then
        fail "'${args[*]}' contains '$actual'"
        return 1
      fi
    done;

    return 0
}

# Usage: assert_equals <expected> <actual>
# Asserts [[ expected == actual ]].
function assert_equals() {
    local expected=$1 actual=$2
    [[ "$expected" == "$actual" ]] && return 0

    local context=""
    if [[ "$#" -eq "3" ]]
    then
      context="${3}: "
    fi
    fail "${context}Expected '$expected', was '$actual'"
    return 1
}

# Usage: assert_not_equals <unexpected> <actual>
# Asserts [[ unexpected != actual ]].
function assert_not_equals() {
    local unexpected=$1 actual=$2
    [[ "$unexpected" != "$actual" ]] && return 0;

    fail "Expected not '${unexpected}', was '${actual}'"
    return 1
}

# Usage: assert_contains <regexp> <file> [error-message]
# Asserts that file matches regexp.  On failure copies the file to undeclared
# outputs, prints the specified (optional) error message, and returns non-zero.
function assert_contains() {
    local pattern=$1
    local file=$2
    local message=${3:-"Expected regexp '$pattern' not found in '$file'"}
    grep -sq -- "$pattern" "$file" && return 0

    fail "$message" $(__copy_to_undeclared_outputs "$file")
    return 1
}

# Usage: assert_not_contains <regexp> <file> [error-message]
# Asserts that file does not match regexp.  On failure copies the file to
# undeclared outputs, prints the specified (optional) error message, and returns
# non-zero.
function assert_not_contains() {
    local pattern=$1
    local file=$2
    local message=${3:-"Expected regexp '$pattern' found in '$file'"}

    if [[ -f "$file" ]]; then
      grep -sq -- "$pattern" "$file" || return 0
    else
      fail "$file is not a file: $message"
      return 1
    fi

    fail "$message" $(__copy_to_undeclared_outputs "$file")
    return 1
}

function assert_contains_n() {
    local pattern=$1
    local expectednum=${2:-1}
    local file=$3
    local message=${4:-"Expected regexp '$pattern' not found exactly $expectednum times in '$file'"}
    local count
    if [[ -f "$file" ]]; then
      count=$(grep -sc -- "$pattern" "$file")
    else
      fail "$file is not a file: $message"
      return 1
    fi
    (( count == expectednum )) && return 0

    fail "$message" $(__copy_to_undeclared_outputs "$file")
    return 1
}

# Usage: assert_exists <file> [error-message]
# Asserts that the file exists.
function assert_exists() {
    local file=$1
    local message=${2:-"Expected '$file' to exist"}
    if [[ -f "$file" ]]; then
        return 0
    fi

    fail "$message"
    return 1
}

# Usage: assert_not_exists <file> [error-message]
# Asserts that the file does not exist.
function assert_not_exists() {
    local file=$1
    local message=${2:-"Expected '$file' to not exist"}
    if ! [[ -f "$file" ]]; then
        return 0
    fi

    fail "$message"
    return 1
}

# Usage: assert_empty_file <file> [error-message]
# Asserts that the file exists and is empty. On failure copies the file to
# undeclared outputs, prints the specified (optional) error message, and returns
# non-zero.
function assert_empty_file() {
    local file=$1
    local message=${2:-"Expected '$file' to exist and be empty"}
    if [[ -f "$file" && ! -s "$file" ]]; then
        return 0
    fi

    fail "$message" $(__copy_to_undeclared_outputs "$file")
    return 1
}

# Usage: assert_nonempty_file <file> [error-message]
# Asserts that the file exists and is nonempty. On failure copies the file to
# undeclared outputs, prints the specified (optional) error message, and returns
# non-zero.
function assert_nonempty_file() {
    local file=$1
    local message=${2:-"Expected '$file' to exist and be nonempty"}
    if [[ -f "$file" && -s "$file" ]]; then
        return 0
    fi

    fail "$message" $(__copy_to_undeclared_outputs "$file")
    return 1
}

# Copies $1 to undeclared outputs with a unique path and logs the mapping
# between the original file and the new file.
function __copy_to_undeclared_outputs() {
  local name=$(basename "$1")
  local testdir="${TEST_UNDECLARED_OUTPUTS_DIR}/${TEST_name}"
  mkdir -p "$testdir"
  local unique_dir=$(mktemp -d -p "$testdir" XXX)
  local newname="${unique_dir}/${name}"
  cp "$1" "$newname"
  echo "Copied '$1' to '$newname'"
}

# Updates the global variables TESTS if
# sharding is enabled, i.e. ($TEST_TOTAL_SHARDS > 0).
function __update_shards() {
    [[ -z "${TEST_TOTAL_SHARDS-}" ]] && return 0

    (( TEST_TOTAL_SHARDS > 0 )) ||
      { echo "Invalid total shards ${TEST_TOTAL_SHARDS}" >&2; exit 1; }

    (( TEST_SHARD_INDEX < 0 || TEST_SHARD_INDEX >= TEST_TOTAL_SHARDS )) &&
      { echo "Invalid shard ${TEST_SHARD_INDEX}" >&2; exit 1; }

    [[ -z "${TEST_SHARD_STATUS_FILE-}" ]] || touch "$TEST_SHARD_STATUS_FILE"

    __evaluate_manual_sharding
    __evaluate_remaining_sharding
    IFS=$' \t\n' read -ra TESTS <<< "${_test_shards[TEST_SHARD_INDEX]}"
}

function __evaluate_manual_sharding() {
  if (( _manual_test_shard_count > TEST_TOTAL_SHARDS )); then
    echo "More manual shards (${_manual_test_shard_count}) defined than"\
        "total shards (${TEST_TOTAL_SHARDS})" >&2
    exit 1;
  fi
  local shard_idx=0
  _test_shard_count=_manual_test_shard_count
  for (( shard_idx=0; shard_idx < _manual_test_shard_count; shard_idx++))
  do
    for test in ${_manual_test_shards[shard_idx]}; do
      grep -q -- "$test" <<<${TESTS[@]} ||
        { echo "define_manual_shard(): '$test' not found in TESTS" >&2
          exit 1; }
    done
    _test_shards[shard_idx]="${_manual_test_shards[shard_idx]}"
  done
}

function __evaluate_remaining_sharding() {
  local test_count=0
  local unshardable_tests=""
  local available_shards=$((${TEST_TOTAL_SHARDS} - ${_manual_test_shard_count}))
  local shard_idx=_manual_test_shard_count
  while (( shard_idx < TEST_TOTAL_SHARDS )); do
     _test_shards[shard_idx]=""
     let shard_idx+=1
  done
  for test in ${TESTS[@]}; do
    _varname="${_manual_sharded_bool_prefix}${test}"
    if [[ -n "${!_varname-}" ]]; then
      continue
    fi
    if (( available_shards > 0 )); then
      let shard_idx=$test_count%available_shards+_manual_test_shard_count 1
      _test_shards[shard_idx]="${_test_shards[shard_idx]} ${test}"
      let test_count+=1
    else
      unshardable_tests="${unshardable_tests} ${test}"
    fi
  done
  if [[ -n "${unshardable_tests}" ]]; then
    echo "There were tests with no explicit shards and every shard was"\
        "manually defined. Increase shard count, assign an explicit shard"\
        "to these tests or remove some manual shards. Affected tests:"\
        "${unshardable_tests}" >&2
    exit 1;
  fi
}

# Usage: define_test_shard <test_name> <test_name> ...
# Makes one of the test shards contain exactly the given tests, if the test
# runs in shards. For non-sharded test execution, this is a no-op.
function define_test_shard() {
    for test in "$@"; do
      _varname="${_manual_sharded_bool_prefix}${test}"
      if [[ -n "${!_varname-}" ]]; then
        echo "define_test_shard(): '$test' already in a shard" >&2
        exit 1;
      fi
      printf -v "${_manual_sharded_bool_prefix}${test}" "%s" "1"
    done
    _manual_test_shards[_manual_test_shard_count++]="$*"
}

# Usage: __test_terminated <signal-number>
# Handler that is called when the test terminated unexpectedly
function __test_terminated() {
    __show_log >&2
    echo "$TEST_name FAILED: terminated by signal $1." >&2
    TEST_passed="false"
    __show_stack
    timeout
    exit 1
}

# Usage: __test_terminated_err
# Handler that is called when the test terminated unexpectedly due to "errexit".
function __test_terminated_err() {
    # When a subshell exits due to signal ERR, its parent shell also exits,
    # thus the signal handler is called recursively and we print out the
    # error message and stack trace multiple times. We're only interested
    # in the first one though, as it contains the most information, so ignore
    # all following.
    if [[ -f $TEST_TMPDIR/__err_handled ]]; then
      exit 1
    fi
    __show_log >&2
    if [[ ! -z "$TEST_name" ]]; then
      echo -n "$TEST_name " >&2
    fi
    echo "FAILED: terminated because this command returned a non-zero status:" >&2
    touch $TEST_TMPDIR/__err_handled
    TEST_passed="false"
    __show_stack
    # If $TEST_name is still empty, the test suite failed before we even started
    # to run tests, so we shouldn't call tear_down.
    if [[ -n "$TEST_name" ]]; then
      __run_tear_down_after_failure
    fi
    exit 1
}

# Usage: __trap_with_arg <handler> <signals ...>
# Helper to install a trap handler for several signals preserving the signal
# number, so that the signal number is available to the trap handler.
function __trap_with_arg() {
    func="$1" ; shift
    for sig ; do
        trap "$func $sig" "$sig"
    done
}

# Usage: <node> <block>
# Adds the block to the given node in the report file. Quotes in the in
# arguments need to be escaped.
function __log_to_test_report() {
    local node="$1"
    local block="$2"
    local xml
    if [[ -e "$XML_OUTPUT_FILE" ]]; then
        xml="$(cat "$XML_OUTPUT_FILE")"
    else
        local xml_header='<?xml version="1.0" encoding="UTF-8"?>'
        xml="${xml_header}<testsuites></testsuites>"
    fi

    local prefix="${xml%%${node}*}"  # Remove everything from node to the end
    local position=${#prefix}  # Length of prefix = position of node in xml
    local suffix="${xml:${position}}"  # Everything from node to the end
    echo "${prefix}${block}${suffix}" > "$XML_OUTPUT_FILE"  # Insert block
}

# Usage: <total> <passed>
# Adds the test summaries to the xml nodes.
function __finish_test_report() {
    local suite_name="$1"
    local total="$2"
    local passed="$3"
    local failed=$((total - passed))

    # Update the xml output with the suite name and total number of
    # passed/failed tests.
    cat "$XML_OUTPUT_FILE" | \
      sed \
        "s/<testsuites>/<testsuites tests=\"$total\" failures=\"0\" errors=\"$failed\">/" | \
      sed \
        "s/<testsuite>/<testsuite name=\"${suite_name}\" tests=\"$total\" failures=\"0\" errors=\"$failed\">/" \
        > "${XML_OUTPUT_FILE}.bak"

    rm -f "$XML_OUTPUT_FILE"
    mv "${XML_OUTPUT_FILE}.bak" "$XML_OUTPUT_FILE"
}

# Multi-platform timestamp function
UNAME=$(uname -s | tr 'A-Z' 'a-z')
if [[ "$UNAME" == "linux" ]] || [[ "$UNAME" =~ msys_nt* ]]; then
    function timestamp() {
      echo $(($(date +%s%N)/1000000))
    }
else
    function timestamp() {
      # macOS and BSDs do not have %N, so Python is the best we can do.
      # LC_ALL=C works around python 3.8 and 3.9 crash on macOS when the
      # filesystem encoding is unspecified (e.g. when LANG=en_US).
      local PYTHON=python
      command -v python3 &> /dev/null && PYTHON=python3
      LC_ALL=C "${PYTHON}" -c 'import time; print(int(round(time.time() * 1000)))'
    }
fi

function get_run_time() {
  local ts_start=$1
  local ts_end=$2
  run_time_ms=$((ts_end - ts_start))
  echo $((run_time_ms / 1000)).${run_time_ms: -3}
}

# Usage: run_tests <suite-comment>
# Must be called from the end of the user's test suite.
# Calls exit with zero on success, non-zero otherwise.
function run_suite() {
  local message="$1"
  # The name of the suite should be the script being run, which
  # will be the filename with the ".sh" extension removed.
  local suite_name="$(basename "$0")"

  echo >&2
  echo "$message" >&2
  echo >&2

  __log_to_test_report "</testsuites>" "<testsuite></testsuite>"

  local total=0
  local passed=0

  atexit "cleanup"

  # If the user didn't specify an explicit list of tests (e.g. a
  # working set), use them all.
  if (( ${#TESTS[@]} == 0 )); then
    # Even if there aren't any tests, this needs to succeed.
    local all_tests=()
    IFS=$'\n' read -d $'\0' -ra all_tests < <(
        declare -F | awk '{print $3}' | grep ^test_ || true; echo -en '\0')

    if (( "${#_TEST_FILTERS[@]}" == 0 )); then
      # Use ${array[@]+"${array[@]}"} idiom to avoid errors when running with
      # Bash version <= 4.4 with `nounset` when `all_tests` is empty (
      # https://github.com/bminor/bash/blob/a0c0a00fc419b7bc08202a79134fcd5bc0427071/CHANGES#L62-L63).
      TESTS=("${all_tests[@]+${all_tests[@]}}")
    else
      for t in "${all_tests[@]+${all_tests[@]}}"; do
        local matches=0
        for f in "${_TEST_FILTERS[@]}"; do
          # We purposely want to glob match.
          # shellcheck disable=SC2053
          [[ "$t" = $f ]] && matches=1 && break
        done
        if (( matches )); then
          TESTS+=("$t")
        fi
      done
    fi

  elif [[ -n "${TEST_WARNINGS_OUTPUT_FILE:-}" ]]; then
    if grep -q "TESTS=" "$TEST_script" ; then
      echo "TESTS variable overridden in sh_test. Please remove before submitting" \
        >> "$TEST_WARNINGS_OUTPUT_FILE"
    fi
  fi

  # Reset TESTS in the common case where it contains a single empty string.
  if [[ -z "${TESTS[*]-}" ]]; then
    TESTS=()
  fi
  local original_tests_size=${#TESTS[@]}

  __update_shards

  if [[ ${#TESTS[@]} -ne 0 ]]; then
    for TEST_name in ${TESTS[@]}; do
      if [[ "${TESTBRIDGE_TEST_RUNNER_FAIL_FAST:-0}" == "1" && "$TEST_passed" == "false" ]]; then
        echo "Skipping test '$TEST_name' due to previous failure and --test_runner_fail_fast set." >&2
        continue
      fi

      >"$TEST_log" # Reset the log.
      TEST_passed="true"

      (( ++total ))
      if [[ "$TEST_verbose" == "true" ]]; then
          date >&2
          __pad "$TEST_name" '*' >&2
      fi

      local run_time="0.0"
      rm -f "${TEST_TMPDIR}"/{__ts_start,__ts_end}

      if [[ "$(type -t "$TEST_name")" == function ]]; then
        # Save exit handlers eventually set.
        local SAVED_ATEXIT="$ATEXIT";
        ATEXIT=

        # Run test in a subshell.
        rm -f "${TEST_TMPDIR}"/__err_handled
        __trap_with_arg __test_terminated INT KILL PIPE TERM ABRT FPE ILL QUIT SEGV

        # Remember -o pipefail value and disable it for the subshell result
        # collection.
        if [[ "${SHELLOPTS}" =~ (^|:)pipefail(:|$) ]]; then
          local __opt_switch=-o
        else
          local __opt_switch=+o
        fi
        set +o pipefail
        (
          set "${__opt_switch}" pipefail
          # if errexit is enabled, make sure we run cleanup and collect the log.
          if [[ "$-" = *e* ]]; then
            set -E
            trap __test_terminated_err ERR
          fi
          timestamp >"${TEST_TMPDIR}"/__ts_start
          testenv_set_up
          set_up
          eval "$TEST_name"
          __in_tear_down=1
          tear_down
          testenv_tear_down
          timestamp >"${TEST_TMPDIR}"/__ts_end
          test "$TEST_passed" == "true"
        ) 2>&1 | tee "${TEST_TMPDIR}"/__log
        # Note that tee will prevent the control flow continuing if the test
        # spawned any processes which are still running and have not closed
        # their stdout.

        test_subshell_status=${PIPESTATUS[0]}
        set "${__opt_switch}" pipefail
        if (( test_subshell_status != 0 )); then
          TEST_passed="false"
          # Ensure that an end time is recorded in case the test subshell
          # terminated prematurely.
          [[ -f "$TEST_TMPDIR"/__ts_end ]] || timestamp >"$TEST_TMPDIR"/__ts_end
        fi

        # Calculate run time for the testcase.
        local ts_start
        ts_start=$(<"${TEST_TMPDIR}"/__ts_start)
        local ts_end
        ts_end=$(<"${TEST_TMPDIR}"/__ts_end)
        run_time=$(get_run_time $ts_start $ts_end)

        # Eventually restore exit handlers.
        if [[ -n "$SAVED_ATEXIT" ]]; then
          ATEXIT="$SAVED_ATEXIT"
          trap "$ATEXIT" EXIT
        fi
      else # Bad test explicitly specified in $TESTS.
        fail "Not a function: '$TEST_name'"
      fi

      local testcase_tag=""

      local red='\033[0;31m'
      local green='\033[0;32m'
      local no_color='\033[0m'

      if [[ "$TEST_verbose" == "true" ]]; then
          echo >&2
      fi

      if [[ "$TEST_passed" == "true" ]]; then
        if [[ "$TEST_verbose" == "true" ]]; then
          echo -e "${green}PASSED${no_color}: ${TEST_name}" >&2
        fi
        (( ++passed ))
        testcase_tag="<testcase name=\"${TEST_name}\" status=\"run\" time=\"${run_time}\" classname=\"\"></testcase>"
      else
        echo -e "${red}FAILED${no_color}: ${TEST_name}" >&2
        # end marker in CDATA cannot be escaped, we need to split the CDATA sections
        log=$(sed 's/]]>/]]>]]&gt;<![CDATA[/g' "${TEST_TMPDIR}"/__log)
        fail_msg=$(cat "${TEST_TMPDIR}"/__fail 2> /dev/null || echo "No failure message")
        # Replacing '&' with '&amp;', '<' with '&lt;', '>' with '&gt;', and '"' with '&quot;'
        escaped_fail_msg=$(echo "$fail_msg" | sed 's/&/\&amp;/g' | sed 's/</\&lt;/g' | sed 's/>/\&gt;/g' | sed 's/"/\&quot;/g')
        testcase_tag="<testcase name=\"${TEST_name}\" status=\"run\" time=\"${run_time}\" classname=\"\"><error message=\"${escaped_fail_msg}\"><![CDATA[${log}]]></error></testcase>"
      fi

      if [[ "$TEST_verbose" == "true" ]]; then
          echo >&2
      fi
      __log_to_test_report "</testsuite>" "$testcase_tag"
    done
  fi

  __finish_test_report "$suite_name" $total $passed
  __pad "${passed} / ${total} tests passed." '*' >&2
  if (( original_tests_size == 0 )); then
    __pad "No tests found." '*'
    exit 1
  elif (( total != passed )); then
    __pad "There were errors." '*' >&2
    exit 1
  elif (( total == 0 )); then
    __pad "No tests executed due to sharding. Check your test's shard_count." '*'
    __pad "Succeeding anyway." '*'
  fi

  exit 0
}