[clocking] Add ScalaTests for the divider-only PLL configurator

generators/chipyard/src/test/scala/clocking/SimplePllConfigurationSpec.scala

@@ -0,0 +1,21 @@
+//See LICENSE for license details.
+package chipyard.clocking
+
+import freechips.rocketchip.prci._
+
+class SimplePllConfigurationSpec extends org.scalatest.FlatSpec {
+
+    def conf(freqMHz: Iterable[Double]): SimplePllConfiguration = new SimplePllConfiguration("test",
+      freqMHz.map({ f => ClockSinkParameters(
+        name = Some(s"desiredFreq_$f"),
+        take = Some(ClockParameters(f))) }).toSeq)
+
+    def tryConf(freqMHz: Double*): Unit = {
+      val freqStr = freqMHz.mkString(", ")
+      it should s"configure for ${freqStr} MHz" in { conf(freqMHz) }
+    }
+
+    tryConf(3200.0, 1600.0, 1000.0, 100.0)
+    tryConf(3200.0, 1600.0)
+    tryConf(3200.0, 1066.7)
+}