Add a basic test suite for pa_hashmap

I spent a little time working through the implementation of
pa_hashmap, and wrote a test suite while doing so.  It tests a few
basic edge cases, like saturating all buckets of the hashtable.

src/Makefile.am

@@ -253,36 +253,37 @@ endif
 noinst_LTLIBRARIES =
 
 TESTS_default = \
-		core-util-test \
-		mainloop-test \
-		strlist-test \
-		close-test \
-		memblockq-test \
-		channelmap-test \
-		thread-mainloop-test \
-		utf8-test \
-		format-test \
-		json-test \
-		get-binary-name-test \
-		hook-list-test \
-		memblock-test \
-		asyncq-test \
-		asyncmsgq-test \
-		queue-test \
-		rtpoll-test \
-		resampler-test \
-		smoother-test \
-		thread-test \
-		volume-test \
-		mix-test \
-		proplist-test \
-		cpu-mix-test \
-		cpu-remap-test \
-		cpu-sconv-test \
-		cpu-volume-test \
-		lock-autospawn-test \
-		mult-s16-test \
-		lfe-filter-test
+        asyncmsgq-test \
+        asyncq-test \
+        channelmap-test \
+        close-test \
+        core-util-test \
+        cpu-mix-test \
+        cpu-remap-test \
+        cpu-sconv-test \
+        cpu-volume-test \
+        format-test \
+        get-binary-name-test \
+        hashmap-test \
+        hook-list-test \
+        json-test \
+        lfe-filter-test \
+        lock-autospawn-test \
+        mainloop-test \
+        memblock-test \
+        memblockq-test \
+        mix-test \
+        mult-s16-test \
+        proplist-test \
+        queue-test \
+        resampler-test \
+        rtpoll-test \
+        smoother-test \
+        strlist-test \
+        thread-mainloop-test \
+        thread-test \
+        utf8-test \
+        volume-test
 
 TESTS_norun = \
 		ipacl-test \
@@ -385,6 +386,11 @@ core_util_test_CFLAGS = $(AM_CFLAGS) $(LIBCHECK_CFLAGS)
 core_util_test_LDADD = $(AM_LDADD) libpulse.la libpulsecommon-@PA_MAJORMINOR@.la
 core_util_test_LDFLAGS = $(AM_LDFLAGS) $(BINLDFLAGS) $(LIBCHECK_LIBS)
 
+hashmap_test_SOURCES = tests/hashmap-test.c
+hashmap_test_CFLAGS = $(AM_CFLAGS) $(LIBCHECK_CFLAGS)
+hashmap_test_LDADD = $(AM_LDADD) libpulse.la libpulsecommon-@PA_MAJORMINOR@.la
+hashmap_test_LDFLAGS = $(AM_LDFLAGS) $(BINLDFLAGS) $(LIBCHECK_LIBS)
+
 mainloop_test_SOURCES = tests/mainloop-test.c
 mainloop_test_CFLAGS = $(AM_CFLAGS) $(LIBCHECK_CFLAGS)
 mainloop_test_LDADD = $(AM_LDADD) libpulse.la libpulsecommon-@PA_MAJORMINOR@.la