cli-test: a tool for testing command-line programs.

Not looking for other users right now, this is just enough to test
unzip/zip/zipinfo.

This includes tests for unzip and ziptool, along with a change to
unzip's behavior to fix AOSP `make dist` when using ziptool unzip.

Also add the boilerplate to run these tests on the device, in presubmit.

Fix command name in --help output.

Test: atest ziptool-tests
Change-Id: I5c0215a3ab8cb2cd5fc517ed9c188f81a7bf4520

Former-commit-id: f276140d0fc0d0f0be8bce3356d69389eb8ab914

cli-test/.clang-format

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+../.clang-format-2

cli-test/Android.bp

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+cc_binary {
+    name: "cli-test",
+    host_supported: true,
+    srcs: ["cli-test.cpp"],
+    cflags: ["-Wall", "-Werror"],
+    shared_libs: ["libbase"],
+}

cli-test/README.md

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+# cli-test
+
+## What?
+
+`cli-test` makes integration testing of command-line tools easier.
+
+## Goals
+
+* Readable syntax. Common cases should be concise, and pretty much anyone
+  should be able to read tests even if they've never seen this tool before.
+
+* Minimal issues with quoting. The toybox tests -- being shell scripts --
+  quickly become a nightmare of quoting. Using a non ad hoc format (such as
+  JSON) would have introduced similar but different quoting issues. A custom
+  format, while annoying, side-steps this.
+
+* Sensible defaults. We expect your exit status to be 0 unless you say
+  otherwise. We expect nothing on stderr unless you say otherwise. And so on.
+
+* Convention over configuration. Related to sensible defaults, we don't let you
+  configure things that aren't absolutely necessary. So you can't keep your test
+  data anywhere except in the `files/` subdirectory of the directory containing
+  your test, for example.
+
+## Non Goals
+
+* Portability. Just being able to run on Linux (host and device) is sufficient
+  for our needs. macOS is probably easy enough if we ever need it, but Windows
+  probably doesn't make sense.
+
+## Syntax
+
+Any all-whitespace line, or line starting with `#` is ignored.
+
+A test looks like this:
+```
+name: unzip -l
+command: unzip -l $FILES/example.zip d1/d2/x.txt
+after: [ ! -f d1/d2/x.txt ]
+expected-stdout:
+	Archive:  $FILES/example.zip
+	  Length      Date    Time    Name
+	---------  ---------- -----   ----
+	     1024  2017-06-04 08:45   d1/d2/x.txt
+	---------                     -------
+	     1024                     1 file
+---
+```
+
+The `name:` line names the test, and is only for human consumption.
+
+The `command:` line is the command to be run. Additional commands can be
+supplied as zero or more `before:` lines (run before `command:`) and zero or
+more `after:` lines (run after `command:`). These are useful for both
+setup/teardown but also for testing post conditions (as in the example above).
+
+Any `command:`, `before:`, or `after:` line is expected to exit with status 0.
+Anything else is considered a test failure.
+
+The `expected-stdout:` line is followed by zero or more tab-prefixed lines that
+are otherwise the exact output expected from the command. (There's magic behind
+the scenes to rewrite the test files directory to `$FILES` because otherwise any
+path in the output would depend on the temporary directory used to run the test.)
+
+There is currently no `expected-stderr:` line. Standard error is implicitly
+expected to be empty, and any output will cause a test failure. (The support is
+there, but not wired up because we haven't needed it yet.)
+
+The fields can appear in any order, but every test must contain at least a
+`name:` line and a `command:` line.
+
+## Output
+
+The output is intended to resemble gtest.
+
+## Future Directions
+
+* It's often useful to be able to *match* against stdout/stderr/a file rather
+  than give exact expected output. We might want to add explicit support for
+  this. In the meantime, it's possible to use an `after:` with `grep -q` if
+  you redirect in your `command:`.
+
+* In addition to using a `before:` (which will fail a test), it can be useful
+  to be able to specify tests that would cause us to *skip* a test. An example
+  would be "am I running as root?".
+
+* It might be useful to be able to make exit status assertions other than 0?
+
+* There's currently no way (other than the `files/` directory) to share repeated
+  setup between tests.