Update hist application to accpet nbins when min/max are not set (#3935)

* Update hist application to accpet nbins when min/max are not set

* Updated history comment on hist test

isis/src/base/apps/hist/hist.xml

@@ -84,6 +84,10 @@
       Updated logic such that min/max values are no longer calculated from .cub
       if values are provided by the user.  Fixes #3881.
     </change>
+    <change name="Kristin Berry" date="2020-06-25">
+      Re-added the ability to set number of bins without setting min/max values after the last update. 
+      Follow-on to #3881.
+    </change>
   </history>
 
   <oldName>

isis/src/base/apps/hist/main.cpp

@@ -57,7 +57,12 @@ void IsisMain() {
   }
   else {
     hist = new Histogram(*icube, 1, p.Progress());
+
+    if (ui.WasEntered("NBINS")){
+      hist->SetBins(ui.GetInteger("NBINS"));
+    }
   }
+
   // Setup the histogram
 
   // Loop and accumulate histogram

isis/src/base/apps/hist/tsts/default/Makefile

@@ -1,9 +1,20 @@
+# 2020-06-25 - Kristin Berry - Added a test to check that if nbins is set, it is used.
+#   To make the truthdata for this test, I set the number of bins to 25, a number much smaller than 
+#   the internal default, and just checked that the output was different from the default test. 
+
 APPNAME = hist
 histTruth.txt.IGNORELINES = Cube
+histTruthNbins.txt.IGNORELINES = Cube
 TEMP = $(OUTPUT)/histTruth.txt
+TEMPNBINS = $(OUTPUT)/histTruthNbins.txt
 
 include $(ISISROOT)/make/isismake.tsts
 
 commands:
+	# Test without additional arguments
 	$(APPNAME) from=$(INPUT)/isisTruth.cub \
-	  to= $(TEMP) > /dev/null;
+	  to=$(TEMP) > /dev/null;
+
+	# Test with setting nbins
+	$(APPNAME) from=$(INPUT)/isisTruth.cub nbins=25\
+	  to=$(TEMPNBINS) > /dev/null;