Tell the fields of a target apart by line breaks only

A target typed in by hand was split into its fields on " / ", which
broke as soon as a field itself contained a slash: an installation
named "ASP/01" gave the box two lines with half a name in each, and
nothing to tell a separator apart from the name. Only a line break now
breaks the text into fields (RealTerminal::cableTarget()), and the
Target cell shows the fields the very same way, one line each
(modelRealTerminalData::targetText()), so the cell and the box under
the cable always read the same text.

The Target cell is edited line by line to go with that: it takes a
multi line editor where Return writes a new line, Ctrl+Return hands
the cell back to the table and Escape throws the text away
(TerminalStripModelDelegate), and the rows of the table are as tall as
the lines their cell shows, so the fields below the first one are never
cut off -- a cell without a target keeps the row it has always had.

The text copied to the clipboard keeps one line per row, the fields of
such a cell joined with " / " again, or a spreadsheet would take them
for several rows.

tst_terminalcableauto reads the three fields of a target of the
drawing back one line each, checks a "/" typed inside a field stays
part of it -- one line holding it, slashes and all -- checks the
editor of the cell is the multi line one, hands its text back
untouched, gives the cell back on Ctrl+Return while Return keeps
writing a new line, and checks the rows grow with the lines the cell
holds and shrink back afterwards. tst_cabletarget paints a strip whose
cable ends on a field containing a slash: the box is no deeper than
with one plain field.

tests/qttest/tst_cabletarget.cpp

@@ -51,9 +51,10 @@
 	Also here: the box at the end of a cable is written at the font of
 	the drawing -- the end zone the settings leave is what gives it the
 	room, so three lines never end up squeezed into a tiny text. A
-	target typed in by hand is written the way the fields are shown in
-	the column, "Installation / Location / Label", and the box draws one
-	line per field, with no slash in it. Two cables of one strip end
+	target typed in by hand is written one line per field, Installation,
+	Location, Label, the way the column shows them, and only a line
+	break breaks it into fields: a "/" written inside a field is part of
+	it, the box draws one line holding it. Two cables of one strip end
 	close to each other, and their boxes are wider than the room between
 	them: the box standing in the way of the other is set lower, its
 	stub drawn longer, and the strip reserves the room for it too.
@@ -529,12 +530,14 @@ void tst_cabletarget::realisticStyleDrawsTheCable()
 }
 
 /**
-	A target typed in by hand is written the way the fields are shown in
-	the column, "Installation / Location / Label": the box under the
-	cable draws one line per field, with no slash in it. The picture of
-	a strip whose cable ends on three fields is therefore that much
-	deeper than the picture of the same strip with one single field --
-	two lines of the font of the drawing.
+	A target typed in by hand is written one line per field, and only a
+	line break breaks it into fields: the box under the cable draws one
+	line per field, with no separator in it. The picture of a strip
+	whose cable ends on three fields is therefore that much deeper than
+	the picture of the same strip with one single field -- two lines of
+	the font of the drawing. A "/" written inside a field, an
+	installation named "Betrieb 1/2", keeps its line: the box is no
+	deeper than with one plain field.
 */
 void tst_cabletarget::typedTargetIsDrawnInItsOwnLines()
 {
@@ -604,9 +607,9 @@ void tst_cabletarget::typedTargetIsDrawnInItsOwnLines()
 	QVERIFY(one_line >= 0);
 
 		//Three fields: the box is two lines deeper, at the font of the
-		//drawing -- the slashes are only there to separate the fields in
-		//the column, the box never draws them
-	type_in(QStringLiteral("Boiler room / Cabinet 3 / -K3"));
+		//drawing -- the fields are written one under the other, the cell
+		//holding them only tells them apart by their line breaks
+	type_in(QStringLiteral("Boiler room\nCabinet 3\n-K3"));
 	QCOMPARE(a_->cableTarget(), (QVector<QString>{QStringLiteral("Boiler room"),
 												  QStringLiteral("Cabinet 3"),
 												  QStringLiteral("-K3")}));
@@ -614,6 +617,16 @@ void tst_cabletarget::typedTargetIsDrawnInItsOwnLines()
 	const QFontMetricsF metrics{pattern_->font()};
 	QVERIFY2(three_lines - one_line > 1.5 * metrics.height(),
 			 "three fields must give a box two lines deeper than one field");
+
+		//A slash written inside a field is part of it: the text gives
+		//one single line, the box is back to the depth of one field and
+		//holds the slash where it was typed
+	type_in(QStringLiteral("Betrieb 1/2 / Keller"));
+	QCOMPARE(a_->cableTarget(),
+			 QVector<QString>{QStringLiteral("Betrieb 1/2 / Keller")});
+	const qreal one_slashed_field{lowest_row(render())};
+	QVERIFY2(qAbs(one_slashed_field - one_line) < metrics.height() / 2,
+			 "a slash inside a field must not split it into lines");
 }
 
 /**
@@ -688,7 +701,7 @@ void tst_cabletarget::boxesOfTwoCablesAreSetApart()
 	second_data_.m_informations.addValue(RealTerminal::cableInfoKey(),
 										 QStringLiteral("X98"));
 	second_data_.m_informations.addValue(RealTerminal::cableTargetInfoKey(),
-										 QStringLiteral("Plant 9 / Cabinet 9 / -S9"));
+										 QStringLiteral("Plant 9\nCabinet 9\n-S9"));
 	second_->setElementData(second_data_);
 	QCOMPARE(b_->cableTarget(),
 			 (QVector<QString>{QStringLiteral("Plant 9"),