From 08049732add4245e0a54174ab9f51008229a3e1e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Simon=20Lars=C3=A9n?= <slarse@slar.se>
Date: Wed, 9 Dec 2020 11:04:13 +0100
Subject: [PATCH] fix(sniper): Fix rounding error in indentation detection on
 single type member (#3722)

---
 .../sniper/internal/IndentationDetector.java  |  4 +--
 .../test/prettyprinter/TestSniperPrinter.java | 25 ++++++++++++++++++-
 .../singletypemember/FourSpaces.java          |  5 ++++
 .../indentation/singletypemember/Tabs.java    |  5 ++++
 .../singletypemember/TwoSpaces.java           |  5 ++++
 5 files changed, 41 insertions(+), 3 deletions(-)
 create mode 100644 src/test/resources/indentation/singletypemember/FourSpaces.java
 create mode 100644 src/test/resources/indentation/singletypemember/Tabs.java
 create mode 100644 src/test/resources/indentation/singletypemember/TwoSpaces.java

diff --git a/src/main/java/spoon/support/sniper/internal/IndentationDetector.java b/src/main/java/spoon/support/sniper/internal/IndentationDetector.java
index 93cd0696507..a3e859e1328 100644
--- a/src/main/java/spoon/support/sniper/internal/IndentationDetector.java
+++ b/src/main/java/spoon/support/sniper/internal/IndentationDetector.java
@@ -79,9 +79,9 @@ private static Pair<Integer, Boolean> guessIndentationStyle(List<String> wsPrece
 			indentationSize = 1;
 		}
 
-		boolean usesTabs = wsPrecedingTypeMembers.stream()
+		boolean usesTabs = (double) wsPrecedingTypeMembers.stream()
 				.filter(s -> s.contains("\t"))
-				.count() >= wsPrecedingTypeMembers.size() / 2;
+				.count() >= (double) wsPrecedingTypeMembers.size() / 2;
 		return Pair.of(indentationSize, usesTabs);
 	}
 
diff --git a/src/test/java/spoon/test/prettyprinter/TestSniperPrinter.java b/src/test/java/spoon/test/prettyprinter/TestSniperPrinter.java
index 99f906010ae..c52f2653b4b 100644
--- a/src/test/java/spoon/test/prettyprinter/TestSniperPrinter.java
+++ b/src/test/java/spoon/test/prettyprinter/TestSniperPrinter.java
@@ -420,7 +420,7 @@ public void testAddedImportStatementPlacedOnSeparateLineInFileWithPackageStateme
 	@Test
 	public void testAddedElementsIndentedWithAppropriateIndentationStyle() {
 		// contract: added elements in a source file should be indented with the same style of
-		// indentation as the rest of the file
+		// indentation as in the rest of the file
 
 		Consumer<CtType<?>> addElements = type -> {
 		    Factory fact = type.getFactory();
@@ -446,6 +446,29 @@ public void testAddedElementsIndentedWithAppropriateIndentationStyle() {
 		testSniper("indentation.FourSpaces", addElements, assertFourSpaces);
 	}
 
+	@Test
+	public void testAddedElementsIndentedWithAppropriateIndentationStyleWhenOnlyOneTypeMemberExists() {
+		// contract: added elements in a source file should be indented with the same style of
+		// indentation as the single type member, when there is only one type member.
+
+		Consumer<CtType<?>> addElement = type -> {
+			Factory fact = type.getFactory();
+			fact.createField(type, new HashSet<>(), fact.Type().INTEGER_PRIMITIVE, "z", fact.createLiteral(2));
+		};
+		final String newField = "int z = 2;";
+
+		BiConsumer<CtType<?>, String> assertTabs = (type, result) ->
+				assertThat(result, containsString("\n\t" + newField));
+		BiConsumer<CtType<?>, String> assertTwoSpaces = (type, result) ->
+				assertThat(result, containsString("\n  " + newField));
+		BiConsumer<CtType<?>, String> assertFourSpaces = (type, result) ->
+				assertThat(result, containsString("\n    " + newField));
+
+		testSniper("indentation.singletypemember.Tabs", addElement, assertTabs);
+		testSniper("indentation.singletypemember.TwoSpaces", addElement, assertTwoSpaces);
+		testSniper("indentation.singletypemember.FourSpaces", addElement, assertFourSpaces);
+	}
+
 	@Test
 	public void testDefaultsToSingleTabIndentationWhenThereAreNoTypeMembers() {
 		// contract: if there are no type members in a compilation unit, the sniper printer defaults
diff --git a/src/test/resources/indentation/singletypemember/FourSpaces.java b/src/test/resources/indentation/singletypemember/FourSpaces.java
new file mode 100644
index 00000000000..50761ee8d42
--- /dev/null
+++ b/src/test/resources/indentation/singletypemember/FourSpaces.java
@@ -0,0 +1,5 @@
+package indentation.singletypemember;
+
+public class FourSpaces {
+    int x;
+}
\ No newline at end of file
diff --git a/src/test/resources/indentation/singletypemember/Tabs.java b/src/test/resources/indentation/singletypemember/Tabs.java
new file mode 100644
index 00000000000..2cc1d5f515e
--- /dev/null
+++ b/src/test/resources/indentation/singletypemember/Tabs.java
@@ -0,0 +1,5 @@
+package indentation.singletypemember;
+
+public class Tabs {
+	int x;
+}
\ No newline at end of file
diff --git a/src/test/resources/indentation/singletypemember/TwoSpaces.java b/src/test/resources/indentation/singletypemember/TwoSpaces.java
new file mode 100644
index 00000000000..8dfe991fb47
--- /dev/null
+++ b/src/test/resources/indentation/singletypemember/TwoSpaces.java
@@ -0,0 +1,5 @@
+package indentation.singletypemember;
+
+public class TwoSpaces {
+  int x;
+}
\ No newline at end of file