test for live template context type; fix a couple of bugs in existing context types

idea/src/org/jetbrains/kotlin/idea/liveTemplates/JetTemplateContextType.java

@@ -43,6 +43,9 @@ public abstract class JetTemplateContextType extends TemplateContextType {
     public boolean isInContext(@NotNull PsiFile file, int offset) {
         if (PsiUtilBase.getLanguageAtOffset(file, offset).isKindOf(JetLanguage.INSTANCE)) {
             PsiElement element = file.findElementAt(offset);
+            if (element == null) {
+                element = file.findElementAt(offset - 1);
+            }
             if (element instanceof PsiWhiteSpace) {
                 return false;
             }
@@ -145,7 +148,7 @@ public abstract class JetTemplateContextType extends TemplateContextType {
                 }
                 e = e.getParent();
             }
-            return true;
+            return e != null;
         }
     }
 

idea/testData/templates/context/InDocComment.kt

@@ -0,0 +1,4 @@
+/**
+ * In <caret>Comment
+ */
+fun foo() {}

idea/testData/templates/context/TopLevel.kt

@@ -0,0 +1 @@
+psvm<caret>

idea/tests/org/jetbrains/kotlin/idea/codeInsight/LiveTemplatesContextTest.kt

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2010-2015 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.idea.codeInsight
+
+import org.jetbrains.kotlin.idea.JetLightCodeInsightFixtureTestCase
+import org.jetbrains.kotlin.idea.PluginTestCaseBase
+
+import java.io.File
+import org.jetbrains.kotlin.idea.liveTemplates.JetTemplateContextType
+import com.intellij.codeInsight.template.TemplateContextType
+import com.intellij.testFramework.UsefulTestCase
+
+public class LiveTemplatesContextTest : JetLightCodeInsightFixtureTestCase() {
+    override fun getTestDataPath(): String =
+            File(PluginTestCaseBase.getTestDataPathBase(), "/templates/context").getPath() + File.separator
+
+    public fun testInDocComment() {
+        myFixture.configureByFile(getTestName(false) + ".kt")
+        assertInContexts(javaClass<JetTemplateContextType.Generic>(), javaClass<JetTemplateContextType.Comment>())
+    }
+
+    public fun testTopLevel() {
+        myFixture.configureByFile(getTestName(false) + ".kt")
+        assertInContexts(javaClass<JetTemplateContextType.Generic>(),
+                         javaClass<JetTemplateContextType.TopLevel>(),
+                         javaClass<JetTemplateContextType.Expression>())
+    }
+
+    private fun assertInContexts(vararg expectedContexts: Class<out JetTemplateContextType>) {
+        val allContexts = TemplateContextType.EP_NAME.getExtensions().filter { it is JetTemplateContextType }
+        val enabledContexts = allContexts.filter { it.isInContext(myFixture.getFile(), myFixture.getCaretOffset()) }.map { it.javaClass }
+        UsefulTestCase.assertSameElements(enabledContexts, *expectedContexts)
+    }
+}