### Question:
CryptographicServiceMessage implements Loggeable { public String getFieldContent(String tag) { return fields.get(tag.toUpperCase()); } CryptographicServiceMessage();  CryptographicServiceMessage(String mcl); void setMCL(String mcl); String getMCL(); void addField(String tag, String content); String getFieldContent(String tag); @Override String toString(); @Override void dump(PrintStream p, String indent); static CryptographicServiceMessage parse(String csmString); static final String MCL_RSI; static final String MCL_KSM; static final String MCL_RSM; static final String MCL_ESM; static final String TAG_RCV; static final String TAG_ORG; static final String TAG_SVR; static final String TAG_KD; static final String TAG_CTP; static final String TAG_CTR; static final String TAG_ERF; }### Answer:
@Test void testGetFieldContent() { instance.setMCL("testMcl"); String result = instance.getFieldContent("testTag"); assertNull(result, "result"); }