Fix broken demo, silent flag swallowing; add tests and LICENSE

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2025 Mike Tisza
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -78,8 +78,16 @@ pip install .
 | `-t TITLE` | Plot title |
 | `-d DELIM` | Output column delimiter for uplot |
 | `--dry-run` | Print the `awk \| uplot` command without running it |
+| `--version` | Show the awkplot version |
 | `--help` | Show usage |
 
+If no awk program and no `-f` are given, awkplot defaults to `{print}`, so
+`something | awkplot` works as a drop-in replacement for bare `uplot`
+(as long as there's data on stdin). Any awkplot/uplot flags must come
+*before* the awk program and input files; flags placed after them are
+rejected with an error instead of being silently forwarded to `awk` as
+bogus input files.
+
 ## Examples
 
 ```bash
@@ -111,3 +119,19 @@ awk [awk-flags] 'program' [files]  |  uplot <type> [uplot-flags]
 ```
 
 `--dry-run` prints the shell-quoted pipeline so you can inspect or tweak it.
+
+## Development
+
+Run the unit tests with:
+
+```bash
+pip install pytest
+pytest
+```
+
+The `examples/demo.sh` script doubles as a smoke test and requires `awk` and
+`uplot` on `PATH`.
+
+## License
+
+MIT — see [LICENSE](LICENSE).

awkplot_cli.py

@@ -5,13 +5,15 @@
 """
 
 import argparse
+import os
 import shlex
 import shutil
-import signal
 import subprocess
 import sys
 
 PLOT_TYPES = ["hist", "bar", "line", "lineplot", "scatter", "density", "box", "count"]
+DEFAULT_PROGRAM = "{print}"
+__version__ = "0.1.0"
 
 
 def build_parser():
@@ -68,6 +70,7 @@ def build_parser():
 
     p.add_argument("--dry-run", dest="dry_run", action="store_true",
                    help="print the command pipeline without executing")
+    p.add_argument("--version", action="version", version=f"%(prog)s {__version__}")
 
     # ── positionals ───────────────────────────────────────────────────────────
     p.add_argument("args", nargs=argparse.REMAINDER,
@@ -97,6 +100,23 @@ def check_deps():
         sys.exit("awkplot: required tools not found on PATH:\n  " + "\n  ".join(missing))
 
 
+def check_leftover_flags(positionals, start=0):
+    """Reject positionals that look like flags awkplot doesn't know about.
+
+    argparse.REMAINDER stops option parsing at the first positional, so any
+    awkplot/uplot flags placed after the awk program (or after -f) would
+    otherwise be silently forwarded to awk as bogus input files. Fail loudly
+    instead of producing a plausible-looking but wrong plot.
+    """
+    for tok in positionals[start:]:
+        if tok.startswith("-") and tok != "-" and not os.path.exists(tok):
+            sys.exit(
+                f"awkplot: unrecognized option {tok!r} found after the awk program/files\n"
+                "  hint: awkplot flags must come before the awk program, "
+                "e.g. awkplot -p bar -t hi '{print $1}' data.csv"
+            )
+
+
 def build_awk_cmd(ns):
     cmd = ["awk"]
     if ns.field_sep is not None:
@@ -109,12 +129,19 @@ def build_awk_cmd(ns):
     positionals = ns.args
     if ns.prog_files:
         # all positionals are input files
+        check_leftover_flags(positionals)
         cmd += positionals
-    else:
-        # first positional is the awk program
-        if not positionals:
+    elif not positionals:
+        # No program and no -f. Default to `{print}` so plain
+        # `something | awkplot` works, but only if there's something to
+        # read; otherwise there's nothing to plot.
+        if sys.stdin.isatty():
             sys.exit("awkplot: awk program required as first positional argument\n"
                      "  hint: awkplot [opts] 'awk program' [file ...]")
+        cmd.append(DEFAULT_PROGRAM)
+    else:
+        # first positional is the awk program
+        check_leftover_flags(positionals, start=1)
         cmd.append(positionals[0])
         cmd += positionals[1:]
 
@@ -154,26 +181,34 @@ def main():
     check_deps()
 
     # ── execute pipeline ───────────────────────────────────────────────────────
-    # Ignore SIGPIPE in the parent so closing the write end doesn't crash us.
-    signal.signal(signal.SIGPIPE, signal.SIG_IGN)
-
     try:
         awk_proc = subprocess.Popen(awk_cmd, stdout=subprocess.PIPE)
-        uplot_proc = subprocess.Popen(uplot_cmd, stdin=awk_proc.stdout)
-        # Let awk_proc receive SIGPIPE if uplot exits early.
-        awk_proc.stdout.close()
-
-        uplot_rc = uplot_proc.wait()
-        awk_rc = awk_proc.wait()
-
+        awk_output, _ = awk_proc.communicate()
+        awk_rc = awk_proc.returncode
     except KeyboardInterrupt:
         sys.exit(130)
     except FileNotFoundError as e:
         sys.exit(f"awkplot: {e}")
 
-    # Surface the first non-zero exit code, awk takes priority.
     if awk_rc != 0:
         sys.exit(awk_rc)
+
+    # uplot produces a confusing Ruby backtrace on empty input; fail clearly
+    # instead of leaking that upstream error to the user.
+    if not awk_output.strip():
+        sys.exit("awkplot: awk produced no output")
+
+    try:
+        uplot_proc = subprocess.Popen(uplot_cmd, stdin=subprocess.PIPE)
+        uplot_proc.communicate(input=awk_output)
+        uplot_rc = uplot_proc.returncode
+    except KeyboardInterrupt:
+        sys.exit(130)
+    except FileNotFoundError as e:
+        sys.exit(f"awkplot: {e}")
+    except BrokenPipeError:
+        uplot_rc = 0
+
     if uplot_rc != 0:
         sys.exit(uplot_rc)
 

examples/demo.sh

@@ -15,12 +15,12 @@ echo "=== 2. Bar chart: letter frequencies in this script ==="
 grep -o '[a-z]' "$0" \
   | sort | uniq -c | sort -rn | head -10 \
   | awk '{print $2, $1}' \
-  | "$AWKPLOT" -p bar -t "Top 10 letters" -H
+  | "$AWKPLOT" -p bar -t "Top 10 letters" -H -d ' '
 
 echo
 echo "=== 3. Scatter: y = x^2 + noise ==="
 awk 'BEGIN { srand(7); for (x=1;x<=60;x++) print x, x*x + (rand()-0.5)*80 }' \
-  | "$AWKPLOT" -p scatter -s 20:60 -c cyan -t "y = x^2 + noise"
+  | "$AWKPLOT" -p scatter -s 20:60 -c cyan -t "y = x^2 + noise" -d ' '
 
 echo
 echo "=== 4. Line: simple sine wave ==="

pyproject.toml

@@ -15,3 +15,7 @@ awkplot = "awkplot_cli:main"
 
 [tool.setuptools]
 py-modules = ["awkplot_cli"]
+
+[tool.pytest.ini_options]
+pythonpath = ["."]
+testpaths = ["tests"]

tests/test_awkplot_cli.py

@@ -0,0 +1,169 @@
+"""Unit tests for awkplot_cli's pure-ish helper functions."""
+
+import argparse
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+import awkplot_cli as cli
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+AWKPLOT_BIN = REPO_ROOT / "awkplot"
+
+
+def make_ns(**overrides):
+    """Build a namespace with build_parser's defaults, overridden as needed."""
+    ns = cli.build_parser().parse_args([])
+    for key, value in overrides.items():
+        setattr(ns, key, value)
+    return ns
+
+
+# ── parse_size ────────────────────────────────────────────────────────────
+
+def test_parse_size_valid():
+    assert cli.parse_size("20:60") == ("20", "60")
+
+
+def test_parse_size_missing_colon():
+    with pytest.raises(SystemExit):
+        cli.parse_size("2060")
+
+
+def test_parse_size_non_integer():
+    with pytest.raises(SystemExit):
+        cli.parse_size("20:sixty")
+
+
+def test_parse_size_empty_part():
+    with pytest.raises(SystemExit):
+        cli.parse_size(":60")
+
+
+# ── build_uplot_cmd ──────────────────────────────────────────────────────
+
+def test_build_uplot_cmd_defaults():
+    ns = make_ns(plot_type="hist")
+    assert cli.build_uplot_cmd(ns) == ["uplot", "hist"]
+
+
+def test_build_uplot_cmd_all_flags():
+    ns = make_ns(
+        plot_type="scatter",
+        header=True,
+        colors="red, blue",
+        size="20:60",
+        title="my title",
+        delimiter=",",
+    )
+    assert cli.build_uplot_cmd(ns) == [
+        "uplot", "scatter",
+        "--header",
+        "--color", "red",
+        "--color", "blue",
+        "--height", "20",
+        "--width", "60",
+        "--title", "my title",
+        "--delimiter", ",",
+    ]
+
+
+# ── build_awk_cmd ────────────────────────────────────────────────────────
+
+def test_build_awk_cmd_basic_program():
+    ns = make_ns(args=["{print $1}", "data.csv"])
+    assert cli.build_awk_cmd(ns) == ["awk", "{print $1}", "data.csv"]
+
+
+def test_build_awk_cmd_with_prog_file():
+    ns = make_ns(prog_files=["prog.awk"], args=["data.csv"])
+    assert cli.build_awk_cmd(ns) == ["awk", "-f", "prog.awk", "data.csv"]
+
+
+def test_build_awk_cmd_forwards_field_sep_and_vars():
+    ns = make_ns(field_sep=",", awk_vars=["t=10"], args=["{print}"])
+    assert cli.build_awk_cmd(ns) == ["awk", "-F", ",", "-v", "t=10", "{print}"]
+
+
+def test_build_awk_cmd_no_program_no_stdin_tty_errors(monkeypatch):
+    monkeypatch.setattr(sys.stdin, "isatty", lambda: True)
+    ns = make_ns(args=[])
+    with pytest.raises(SystemExit):
+        cli.build_awk_cmd(ns)
+
+
+def test_build_awk_cmd_no_program_defaults_when_stdin_has_data(monkeypatch):
+    # Regression test for the demo.sh bug: `something | awkplot` with no
+    # awk program should default to `{print}` instead of erroring out.
+    monkeypatch.setattr(sys.stdin, "isatty", lambda: False)
+    ns = make_ns(args=[])
+    assert cli.build_awk_cmd(ns) == ["awk", cli.DEFAULT_PROGRAM]
+
+
+def test_build_awk_cmd_rejects_leftover_flags_after_program():
+    # Regression test: flags placed after the awk program used to be
+    # silently forwarded to awk as bogus input files.
+    ns = make_ns(args=["{print $1}", "d.csv", "-p", "bar", "-t", "hi"])
+    with pytest.raises(SystemExit):
+        cli.build_awk_cmd(ns)
+
+
+def test_build_awk_cmd_rejects_leftover_flags_with_prog_file():
+    ns = make_ns(prog_files=["prog.awk"], args=["data.csv", "--dry-run"])
+    with pytest.raises(SystemExit):
+        cli.build_awk_cmd(ns)
+
+
+def test_build_awk_cmd_allows_existing_file_starting_with_dash(tmp_path, monkeypatch):
+    weird_file = tmp_path / "-weird.csv"
+    weird_file.write_text("1,2\n")
+    monkeypatch.chdir(tmp_path)
+    ns = make_ns(args=["{print}", "-weird.csv"])
+    assert cli.build_awk_cmd(ns) == ["awk", "{print}", "-weird.csv"]
+
+
+# ── CLI-level (dry-run) smoke tests ──────────────────────────────────────
+
+def run_cli(args):
+    return subprocess.run(
+        [str(AWKPLOT_BIN), *args],
+        capture_output=True,
+        text=True,
+        cwd=REPO_ROOT,
+    )
+
+
+def test_cli_dry_run_default_program_with_stdin():
+    result = subprocess.run(
+        [str(AWKPLOT_BIN), "--dry-run", "-p", "hist"],
+        input="1\n2\n3\n",
+        capture_output=True,
+        text=True,
+        cwd=REPO_ROOT,
+    )
+    assert result.returncode == 0
+    assert result.stdout.strip() == "awk '{print}' | uplot hist"
+
+
+def test_cli_dry_run_leftover_flags_error_out():
+    result = run_cli(["--dry-run", "{print $1}", "d.csv", "-p", "bar", "-t", "hi"])
+    assert result.returncode != 0
+    assert "unrecognized option" in result.stderr
+
+
+def test_cli_dry_run_basic():
+    result = run_cli(["--dry-run", "-F,", "-p", "scatter", "-c", "red",
+                       "-s", "20:60", "-H", "{print $2,$5}", "data.csv"])
+    assert result.returncode == 0
+    assert result.stdout.strip() == (
+        "awk -F , '{print $2,$5}' data.csv | "
+        "uplot scatter --header --color red --height 20 --width 60"
+    )
+
+
+def test_cli_version():
+    result = run_cli(["--version"])
+    assert result.returncode == 0
+    assert "awkplot" in result.stdout