fits: testcase for nasty nom-tam-fits v1.15.2 behaviour

Add testcase that tests for unwanted quote manipulation when
constructing a string-valued header using nom.tam.fits.HeaderCard.

This works fine with the ancient bundled nom.tam.fits (v0.96?)
but will fail if used with the newer nom-tam-fits v1.15.2.
See nom-tam-fits/nom-tam-fits#148

fits/src/testcases/uk/ac/starlink/fits/TamfitsTest.java

@@ -79,6 +79,7 @@ public void testString() throws Exception {
         }
     }
 
+
     private void checkStringCard( HeaderCard card ) {
         String image = card.toString();
         assertEquals( 80, image.length() );
@@ -93,6 +94,24 @@ private void checkStringCard( HeaderCard card ) {
         }
     }
 
+    public void testStringValues() throws Exception {
+        checkStringValue( "electron'.s**-1" );
+        checkStringValue( "x'electron'.s**-1" );
+
+        // This one fails for nom.tam.fits 1.15.2;
+        // the HeaderCard constructor checks for a quote at the start of
+        // the string and assumes that you have pre-quoted the value,
+        // tries to strip quotes from start and end, and fails if
+        // it can't.  That is horrible behaviour.
+        // See https://github.com/nom-tam-fits/nom-tam-fits/issues/148
+        checkStringValue( "'electron'.s**-1" );
+    }
+
+    private void checkStringValue( String sval ) throws Exception {
+        HeaderCard card = new HeaderCard( "CARD", sval, "comment" );
+        assertEquals( sval, card.getValue() );
+    }
+
     private static String repeat( String txt, int count ) {
         StringBuffer sbuf = new StringBuffer( txt.length() * count );
         for ( int i = 0; i < count; i++ ) {