added simple test case for epicsEnvUnset

src/libCom/test/Makefile

@@ -62,6 +62,11 @@ epicsEnvTest_SRCS += epicsEnvTest.c
 testHarness_SRCS += epicsEnvTest.c
 TESTS += epicsEnvTest
 
+TESTPROD_HOST += epicsEnvUnsetTest
+epicsEnvUnsetTest_SRCS += epicsEnvUnsetTest.c
+testHarness_SRCS += epicsEnvUnsetTest.c
+TESTS += epicsEnvUnsetTest
+
 TESTPROD_HOST += epicsErrlogTest
 epicsErrlogTest_SRCS += epicsErrlogTest.c
 testHarness_SRCS += epicsErrlogTest.c

src/libCom/test/epicsEnvUnsetTest.c

@@ -0,0 +1,38 @@
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "macLib.h"
+#include "envDefs.h"
+#include "errlog.h"
+#include "epicsUnitTest.h"
+#include "testMain.h"
+
+static void check(const char* variable, const char* expected)
+{
+    const char* value;
+    
+    value = getenv(variable);
+    if (!testOk((!expected && !value) || (expected && value && strcmp(expected, value) == 0),
+        "%s = \"%s\"", variable, value))
+    {
+        testDiag("should have been \"%s\"", expected);
+    }
+}
+
+
+MAIN(epicsEnvUnsetTest)
+{
+    eltc(0);
+    testPlan(3);
+
+    check("TEST_VAR_A",NULL);
+    epicsEnvSet("TEST_VAR_A","test value");
+    check("TEST_VAR_A","test value");
+    epicsEnvUnset("TEST_VAR_A");
+    check("TEST_VAR_A",NULL);
+
+    testDone();
+    return 0;
+}