测试固件、临时环境与覆盖率

为什么测试夹具和隔离很重要

创建和清理临时目录

#!/usr/bin/env bash
set -euo pipefail

# Create an isolated temp directory
TMPDIR=$(mktemp -d)
# Always clean up, even if the script exits early or errors out
trap 'rm -rf "$TMPDIR"' EXIT

echo "Working in: $TMPDIR"

# Simulate creating fixture files
mkdir -p "$TMPDIR/project/{src,tests,logs}"
echo 'version=1.2.3' > "$TMPDIR/project/.env"
echo 'Hello fixture' > "$TMPDIR/project/src/main.sh"

ls -R "$TMPDIR/project"
echo 'Temp dir will be removed automatically on exit'

组织测试夹具目录树

#!/usr/bin/env bash
# fixture_helpers.bash — source this from your test files

FIXTURE_ROOT=''

setup_fixture() {
  FIXTURE_ROOT=$(mktemp -d)
  # Build the directory tree the deploy script expects
  mkdir -p "$FIXTURE_ROOT"/{dist,config,logs}
  echo '{"version":"2.0"}' > "$FIXTURE_ROOT/config/app.json"
  echo 'console.log("app")' > "$FIXTURE_ROOT/dist/index.js"
  touch "$FIXTURE_ROOT/logs/.gitkeep"
  export FIXTURE_ROOT
  echo "[setup] Fixture ready at $FIXTURE_ROOT"
}

teardown_fixture() {
  if [[ -n "$FIXTURE_ROOT" && -d "$FIXTURE_ROOT" ]]; then
    rm -rf "$FIXTURE_ROOT"
    echo '[teardown] Fixture removed'
  fi
}

# Self-test
setup_fixture
ls "$FIXTURE_ROOT"
teardown_fixture

使用伪造的 PATH 模拟可执行文件

#!/usr/bin/env bash
set -euo pipefail

FIXTURE=$(mktemp -d)
trap 'rm -rf "$FIXTURE"' EXIT

# Create a fake 'curl' that records calls and returns canned data
FAKE_BIN="$FIXTURE/bin"
mkdir -p "$FAKE_BIN"

cat > "$FAKE_BIN/curl" << 'SCRIPT'
#!/usr/bin/env bash
# Log every argument for later inspection
echo "curl $*" >> "$FIXTURE_BIN_LOG"
# Return a canned HTTP 200 response body
echo '{"status":"ok","id":42}'
SCRIPT
chmod +x "$FAKE_BIN/curl"

# Export the log path so the fake can find it
export FIXTURE_BIN_LOG="$FIXTURE/curl_calls.log"

# Prepend fake bin directory to PATH
export PATH="$FAKE_BIN:$PATH"

# Now any call to 'curl' hits our fake
curl -s https://api.example.com/health
curl -X POST https://api.example.com/deploy

echo '--- Recorded curl calls ---'
cat "$FIXTURE_BIN_LOG"

捕获并断言命令输出

#!/usr/bin/env bash
set -euo pipefail

# Minimal assertion helpers
assert_eq() {
  local desc="$1" expected="$2" actual="$3"
  if [[ "$expected" == "$actual" ]]; then
    echo "PASS: $desc"
  else
    echo "FAIL: $desc"
    echo "  expected: $expected"
    echo "  actual:   $actual"
    return 1
  fi
}

assert_file_exists() {
  local desc="$1" file="$2"
  if [[ -f "$file" ]]; then
    echo "PASS: $desc"
  else
    echo "FAIL: $desc — file not found: $file"
    return 1
  fi
}

assert_contains() {
  local desc="$1" needle="$2" haystack="$3"
  if [[ "$haystack" == *"$needle"* ]]; then
    echo "PASS: $desc"
  else
    echo "FAIL: $desc — '$needle' not found in output"
    return 1
  fi
}

# Demo usage
TMPDIR=$(mktemp -d)
trap 'rm -rf "$TMPDIR"' EXIT
echo 'hello world' > "$TMPDIR/greeting.txt"
OUT=$(cat "$TMPDIR/greeting.txt")
assert_eq   'file content matches'     'hello world' "$OUT"
assert_file_exists 'greeting file created' "$TMPDIR/greeting.txt"
assert_contains    'output has hello'     'hello'       "$OUT"

测试中的环境变量作用域

#!/usr/bin/env bash
set -euo pipefail

FIXTURE=$(mktemp -d)
trap 'rm -rf "$FIXTURE"' EXIT

# Write a tiny script under test that reads env vars
cat > "$FIXTURE/deploy.sh" << 'SCRIPT'
#!/usr/bin/env bash
set -euo pipefail
ENV_NAME=${DEPLOY_ENV:-unknown}
CFG=${CONFIG_DIR:-/etc/app}
echo "Deploying to $ENV_NAME using config from $CFG"
SCRIPT
chmod +x "$FIXTURE/deploy.sh"

echo '--- Test 1: staging env ---'
# Run in a clean subshell with explicit vars
(
  export DEPLOY_ENV=staging
  export CONFIG_DIR="$FIXTURE/config"
  "$FIXTURE/deploy.sh"
)

echo '--- Test 2: production env ---'
(
  export DEPLOY_ENV=production
  export CONFIG_DIR=/etc/prod-config
  "$FIXTURE/deploy.sh"
)

echo '--- Test 3: defaults ---'
# No env vars set — script should use its own defaults
env -i PATH="$PATH" "$FIXTURE/deploy.sh"

Bash 覆盖率简介：kcov

对真实脚本运行 kcov

#!/usr/bin/env bash
# This demo shows the *structure* of a kcov workflow.
# It will not run kcov itself (not guaranteed to be installed),
# but the script under test and test runner are fully runnable.
set -euo pipefail

FIXTURE=$(mktemp -d)
trap 'rm -rf "$FIXTURE"' EXIT

# 1. Script under test
cat > "$FIXTURE/process.sh" << 'SCRIPT'
#!/usr/bin/env bash
set -euo pipefail
INPUT="$1"
if [[ ! -f "$INPUT" ]]; then
  echo "ERROR: file not found" >&2
  exit 1
fi
LINE_COUNT=$(wc -l < "$INPUT")
if (( LINE_COUNT == 0 )); then
  echo "WARNING: file is empty"
else
  echo "Processed $LINE_COUNT lines"
fi
SCRIPT
chmod +x "$FIXTURE/process.sh"

# 2. Happy path test (exercises line 6 and 11)
echo -e 'one\ntwo\nthree' > "$FIXTURE/data.txt"
OUT=$("$FIXTURE/process.sh" "$FIXTURE/data.txt")
echo "Happy path: $OUT"

# 3. Empty file test (exercises line 9)
touch "$FIXTURE/empty.txt"
OUT=$("$FIXTURE/process.sh" "$FIXTURE/empty.txt")
echo "Empty file: $OUT"

# 4. Missing file test (exercises line 5-6)
if ! OUT=$("$FIXTURE/process.sh" "$FIXTURE/missing.txt" 2>&1); then
  echo "Missing file (expected error): $OUT"
fi

# To measure coverage, wrap each call with kcov:
# kcov --include-path="$FIXTURE" "$FIXTURE/cov/happy" "$FIXTURE/process.sh" ...
# kcov --merge "$FIXTURE/cov/all" "$FIXTURE/cov/happy" "$FIXTURE/cov/empty"

合并多次测试运行的覆盖率

#!/usr/bin/env bash
# extract_coverage.sh — parse kcov JSON and fail below threshold
set -euo pipefail

MIN_COVERAGE=80   # percent
COV_JSON="${1:-coverage-out/myscript.sh/coverage.json}"

if [[ ! -f "$COV_JSON" ]]; then
  echo "ERROR: coverage JSON not found at $COV_JSON" >&2
  exit 1
fi

# kcov JSON contains a key like: "percent_covered": "87.50"
PERCENT=$(grep -oP '"percent_covered":\s*"\K[0-9.]+' "$COV_JSON")
PERCENT_INT=${PERCENT%%.*}   # truncate decimal

echo "Coverage: ${PERCENT}%  (minimum: ${MIN_COVERAGE}%)"

if (( PERCENT_INT < MIN_COVERAGE )); then
  echo "FAIL: coverage ${PERCENT}% is below threshold ${MIN_COVERAGE}%" >&2
  exit 1
fi

echo "PASS: coverage threshold met"

分支覆盖率与行覆盖率

#!/usr/bin/env bash
# Illustrates line vs branch coverage gap
set -euo pipefail

check_file() {
  local f="$1"
  if [[ -f "$f" ]]; then        # branch A (true) OR branch B (false)
    local lines
    lines=$(wc -l < "$f")
    if (( lines > 0 )); then    # branch C (true) OR branch D (false)
      echo "File has $lines lines"
    else
      echo "File is empty"     # branch D — unreached if only tested with non-empty file
    fi
  else
    echo "File missing"        # branch B — unreached if only tested with existing file
  fi
}

# Only one test: covers lines 5-10 (4 of 6 branches)
TMPDIR=$(mktemp -d)
trap 'rm -rf "$TMPDIR"' EXIT
echo 'data' > "$TMPDIR/sample.txt"
check_file "$TMPDIR/sample.txt"

# To reach 100% branch coverage you also need:
# check_file "/nonexistent/path"
# check_file "$TMPDIR/empty.txt" (after: touch "$TMPDIR/empty.txt")

在持续集成中整合固定装置与覆盖率

#!/usr/bin/env bash
# ci_runner.sh — full fixture + coverage pipeline entry point
set -euo pipefail

SRC="./src/deploy.sh"
COV_ROOT="$(mktemp -d)/coverage"
trap 'rm -rf "$COV_ROOT"' EXIT
mkdir -p "$COV_ROOT"

PASS=0
FAIL=0
RUN_NUM=0

run_test() {
  local name="$1" test_fn="$2"
  local fixture
  fixture=$(mktemp -d)
  local cov_out="$COV_ROOT/run_$((++RUN_NUM))"

  if (
    trap 'rm -rf "$fixture"' EXIT
    export FIXTURE="$fixture"
    # Fake bin directory shadowing real tools
    mkdir -p "$fixture/bin"
    export PATH="$fixture/bin:$PATH"
    "$test_fn" "$fixture"
  ); then
    echo "PASS: $name"
    (( PASS++ )) || true
  else
    echo "FAIL: $name"
    (( FAIL++ )) || true
  fi
}

# Example test function
test_happy_path() {
  local fx="$1"
  mkdir -p "$fx/dist"
  echo 'app.js' > "$fx/dist/index.js"
  # Would normally run: kcov "$cov_out" "$SRC" --env=staging "$fx"
  echo "[test] happy path executed in $fx"
}

run_test 'happy_path' test_happy_path

echo "Results: $PASS passed, $FAIL failed"
(( FAIL == 0 ))

知识检查：伪造 PATH 技巧

回顾：固定装置、临时环境与覆盖率