Add tests for assert, abort, and environ. (#105)

To support this, add a mechanism for filtering test output to filter
out uninteresting diffs.

This adds some coverage for the code being changed in
https://github.com/WebAssembly/wasi-libc/pull/184.

tests/.gitignore

@@ -1,2 +1,3 @@
 *.observed
+*.observed.filtered
 *.wasm

tests/general/abort.c

@@ -0,0 +1,6 @@
+#include <stdlib.h>
+
+int main(void) {
+    abort();
+    return 0;
+}

tests/general/abort.c.exit_status.expected

@@ -0,0 +1 @@
+134

tests/general/abort.c.stderr.expected

@@ -0,0 +1,6 @@
+Error: failed to run main module `abort.c.---.wasm`
+
+Caused by:
+    0: failed to invoke `_start`
+    1: wasm trap: unreachable, source location: @----
+       wasm backtrace:

tests/general/abort.c.stderr.expected.filter

@@ -0,0 +1,7 @@
+#!/bin/bash
+set -euo pipefail
+
+cat \
+    | sed -e 's/main module `abort\.c\.[^`]*\.wasm`/main module `abort.c.---.wasm`/' \
+    | sed -e 's/source location: @[[:xdigit:]]*$/source location: @----/' \
+    | head -n 6

tests/general/assert-fail.c

@@ -0,0 +1,7 @@
+#include <assert.h>
+#include <stdbool.h>
+
+int main(void) {
+    assert(false);
+    return 0;
+}

tests/general/assert-fail.c.exit_status.expected

@@ -0,0 +1 @@
+134

tests/general/assert-fail.c.stderr.expected

@@ -0,0 +1,7 @@
+Assertion failed: false (assert-fail.c: main: 5)
+Error: failed to run main module `assert-fail.c.---.wasm`
+
+Caused by:
+    0: failed to invoke `_start`
+    1: wasm trap: unreachable, source location: @----
+       wasm backtrace:

tests/general/assert-fail.c.stderr.expected.filter

@@ -0,0 +1,7 @@
+#!/bin/bash
+set -euo pipefail
+
+cat \
+    | sed -e 's/main module `assert-fail\.c\.[^`]*\.wasm`/main module `assert-fail.c.---.wasm`/' \
+    | sed -e 's/source location: @[[:xdigit:]]*$/source location: @----/' \
+    | head -n 7

tests/general/assert-pass.c

@@ -0,0 +1,7 @@
+#include <assert.h>
+#include <stdbool.h>
+
+int main(void) {
+    assert(true);
+    return 0;
+}

tests/general/environ.c

@@ -0,0 +1,18 @@
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+extern char **environ;
+
+int main(void) {
+    assert(environ != NULL);
+    for (char **p = environ; *p; ++p) {
+        assert(p != NULL);
+    }
+    for (char **p = environ; *p; ++p) {
+        if (strncmp(*p, "HELLO=", 5) == 0) {
+            printf("HELLO = %s\n", *p + 6);
+        }
+    }
+    return 0;
+}

tests/general/environ.c.env

@@ -0,0 +1 @@
+HELLO=hello

tests/general/environ.c.stdout.expected

@@ -0,0 +1 @@
+HELLO = hello

tests/testcase.sh

@@ -60,11 +60,27 @@ echo $exit_status > "$exit_status_observed"
 # Determine the reference files to compare with.
 if [ -e "$input.stdout.expected" ]; then
   stdout_expected="$input.stdout.expected"
+
+  # Apply output filters.
+  if [ -e "$input.stdout.expected.filter" ]; then
+      cat "$stdout_observed" \
+          | "$input.stdout.expected.filter" \
+          > "${stdout_observed}.filtered"
+      stdout_observed="${stdout_observed}.filtered"
+  fi
 else
   stdout_expected="/dev/null"
 fi
 if [ -e "$input.stderr.expected" ]; then
   stderr_expected="$input.stderr.expected"
+
+  # Apply output filters.
+  if [ -e "$input.stderr.expected.filter" ]; then
+      cat "$stderr_observed" \
+          | "./$input.stderr.expected.filter" \
+          > "${stderr_observed}.filtered"
+      stderr_observed="${stderr_observed}.filtered"
+  fi
 else
   stderr_expected="/dev/null"
 fi