Add test coverage for isInitialized in MemoizingInterruptibleSupplier.

RELNOTES: None.
PiperOrigin-RevId: 248746530

src/test/java/com/google/devtools/build/lib/supplier/MemoizingInterruptibleSupplierTest.java

diff --git a/src/test/java/com/google/devtools/build/lib/supplier/MemoizingInterruptibleSupplierTest.java b/src/test/java/com/google/devtools/build/lib/supplier/MemoizingInterruptibleSupplierTest.java
index 93967fd..5408e72 100644
--- a/src/test/java/com/google/devtools/build/lib/supplier/MemoizingInterruptibleSupplierTest.java
+++ b/src/test/java/com/google/devtools/build/lib/supplier/MemoizingInterruptibleSupplierTest.java
@@ -37,7 +37,7 @@
   }
 
   @Test
-  public void returnsCorrectResult() throws Exception {
+  public void getReturnsCorrectResult() throws Exception {
     MemoizingInterruptibleSupplier<String> supplier =
         MemoizingInterruptibleSupplier.of(callCounter::call);
     returnVal = "abc";
@@ -48,6 +48,18 @@
   }
 
   @Test
+  public void subsequentCallToGetReturnsCorrectResult() throws Exception {
+    MemoizingInterruptibleSupplier<String> supplier =
+        MemoizingInterruptibleSupplier.of(callCounter::call);
+    returnVal = "abc";
+
+    supplier.get();
+    String result = supplier.get();
+
+    assertThat(result).isEqualTo("abc");
+  }
+
+  @Test
   public void onlyCallsDelegateOnce() throws Exception {
     MemoizingInterruptibleSupplier<String> supplier =
         MemoizingInterruptibleSupplier.of(callCounter::call);
@@ -71,6 +83,39 @@
   }
 
   @Test
+  public void notInitializedBeforeCallingGet() {
+    MemoizingInterruptibleSupplier<String> supplier =
+        MemoizingInterruptibleSupplier.of(callCounter::call);
+
+    boolean initialized = supplier.isInitialized();
+
+    assertThat(initialized).isFalse();
+  }
+
+  @Test
+  public void isInitializedAfterCallingGet() throws Exception {
+    MemoizingInterruptibleSupplier<String> supplier =
+        MemoizingInterruptibleSupplier.of(callCounter::call);
+
+    supplier.get();
+    boolean initialized = supplier.isInitialized();
+
+    assertThat(initialized).isTrue();
+  }
+
+  @Test
+  public void isStillInitializedAfterSubsequentCallToGet() throws Exception {
+    MemoizingInterruptibleSupplier<String> supplier =
+        MemoizingInterruptibleSupplier.of(callCounter::call);
+
+    supplier.get();
+    supplier.get();
+    boolean initialized = supplier.isInitialized();
+
+    assertThat(initialized).isTrue();
+  }
+
+  @Test
   public void of_returnsSameInstanceIfAlreadyMemoizing() {
     InterruptibleSupplier<String> supplier = MemoizingInterruptibleSupplier.of(callCounter::call);
     assertThat(MemoizingInterruptibleSupplier.of(supplier)).isSameInstanceAs(supplier);