diff --git a/README.md b/README.md
index 497ebb1de0f0..e557eb435316 100644
--- a/README.md
+++ b/README.md
@@ -56,6 +56,7 @@ extras pull in everything the suite needs:
 
 ```
 pip install -e ".[tests]"
+tests/run-tests.sh
 ```
 
 See [tests/docs/](tests/docs/) for how to run the suite and the
diff --git a/tests/run-tests.sh b/tests/run-tests.sh
new file mode 100755
index 000000000000..9db6d50338d6
--- /dev/null
+++ b/tests/run-tests.sh
@@ -0,0 +1,75 @@
+#!/usr/bin/env bash
+#
+# Run the wic test suite.
+#
+# Thin wrapper around pytest that works from anywhere in the checkout:
+# it locates the repository root, makes sure the interpreter can import
+# wic, and then hands off to pytest.
+#
+# Needs the test extras: pip install -e ".[tests]"
+
+set -euo pipefail
+
+usage() {
+    cat <<'USAGE'
+Usage:
+  tests/run-tests.sh [pytest args]
+
+Options:
+  -h, --help    show this help and exit
+
+Anything else is passed straight through to pytest (for example a
+path, -k EXPR, or -v). With no such argument the whole suite under
+tests/ is run.
+
+Examples:
+  tests/run-tests.sh                  # whole suite
+  tests/run-tests.sh -k filemap -v    # pass args through to pytest
+  tests/run-tests.sh tests/unit       # a single tier or file
+
+Needs the test extras: pip install -e ".[tests]"
+USAGE
+}
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+PY="${PYTHON:-python3}"
+
+pytest_args=()
+while [ $# -gt 0 ]; do
+    case "$1" in
+        -h|--help)
+            usage
+            exit 0
+            ;;
+        --)
+            shift
+            pytest_args+=("$@")
+            break
+            ;;
+        *)
+            pytest_args+=("$1")
+            ;;
+    esac
+    shift
+done
+
+cd "$REPO_ROOT"
+
+# Make sure the interpreter that will run pytest can actually import wic.
+# The suites pass even without an install (each adds src/ to sys.path),
+# but the session banner and any install-dependent behaviour would be
+# wrong, so fail loudly instead of running against the wrong interpreter.
+if ! "$PY" -c "import wic" >/dev/null 2>&1; then
+    echo "error: '$PY' cannot import wic." >&2
+    echo "       install wic with its test extras:" >&2
+    echo "       $PY -m pip install -e \".[tests]\"" >&2
+    exit 1
+fi
+
+# Default target: the whole suite. Overridden if the caller passed a
+# path or -k/-m selector to pytest.
+if [ ${#pytest_args[@]} -eq 0 ]; then
+    pytest_args=("tests")
+fi
+
+exec "$PY" -m pytest "${pytest_args[@]}"